June 2012 | Australian Journal of Crop Science| AJCS

Characterization of thermo-sensitive genic male sterility (TGMS) rice genotypes (Oryza sativa L.) at different altitudes

R. K. Salgotra, B. B. Gupta and M. I. AhmedDivision of Plant Breeding and Genetics, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Chatha, Jammu-180 009 (J & K), India
Hybrid Rice Section, Directorate of Rice Research (ICAR), Rajendera Nagar, Hyderabad (A.P.) India
Abstract
Thermo-sensitive genic male sterility (TGMS) is the genic sterile system in plants that affects the fertility/sterility response to temperature in hybrid rice breeding. Eight TGMS lines, DDR 1S, DDR 18S, DDR 19S, DDR 20S, DDR 23S, DDR 27S, DRR 28S and DDR 29, showed satisfactory seed-set percentage at high altitude, but complete sterility at low altitude. Characterization of sterility-sensitive stage and floral traits were determined by the tracking method. At low altitude, with an average air temperature of 35.4 °C, TGMS lines DRR 19S, DRR 20S and DRR 29S displayed a sterility-sensitive stage at 21 days prior to normal heading. The TGMS line DRR 1S required a temperature of 36.6 °C for complete sterility at 17 days prior to normal heading. In the remaining seven lines, the temperature for complete sterility ranged from 33.9 °C to 35.8 °C at low altitude. Angle of opened lemma and palea showed a significantly positive correlation with opening duration of lemma and palea and with size of stigma.

Pages 957-962 | Full Text PDF

Investigation of polyacrylamide application under different tillage intensity on sediment and nitrogen losses in irrigated corn field

Majid Roozbeh, Hooshang Bahrami, Morteza Almassi, M.J. Sheikhdavoodi, Fariborz Abbasi, Mahdi Gheysari

Department of Agricultural Machinery Engineering and Mechanization, Faculty of Agriculture, Shahid Chamran University, Ahwaz, Iran
Water Engineering Department, Agricultural Engineering Research Institute, Karaj, Iran
Water Engineering Department, College of Agriculture, Isfahan University of Technology, Isfahan, Iran

Abstract
Degradation of agricultural soils and nutrient losses affected by intensive agriculture and tillage are some of the environmental and agricultural concerns. These concerns lead to emergence and development of conservative technologies such as conservation tillage systems [(RT),(NT)] and anionic polyacrylamide (PAM). A study was conducted to determine the consequences of three tillage systems and anionic polyacrylamide on sediment loss, runoff nitrate concentration, nitrogen losses from the soil-plant system and nitrogen recovery. The experimental design was a randomized complete block with split-plot arranged in three replications. The anionic polyacrylamide (PAM) were in three levels of zero (P0), 10 (P10) and 20 (P20) mg L^-1 as the main plot and different tillage intensities as the subplot including moldboard plowing plus two disk harrow passes (CT1), one stubble cultivator pass (RT) and moldboard plowing plus one power harrow pass (CT2). PAM was applied only in the first irrigation and during the advance water flow before runoff began. The results showed that tillage treatments and PAM had a significant effect on reduction of sediment transfer and soil loss. The RT treatment relative to CT2 led to soil loss reduction by 52.7% during the first irrigation. The P10 and P20 treatments compared to P0, caused sediment concentration reduction by 94.6 and 95.2% and soil loss reduction by 96.4 and 96.7%, respectively. The RT × P20 treatment had a greater impact in reduction of runoff nitrate losses than CT1 × P20 and CT2 × P20 treatments. Losses of nitrogen in the fertilized plots and RAN were influenced by both tillage system and PAM application.

Pages 963-969 | Full Text PDF

Morphological and molecular characterization of cereal cyst nematode (Heterodera avenae) populations from arid environments

Ahmed A.M. Dawabah, Ahmad S. Al-Hazmi, Soloiman M. Al-Rehiayani, Ahmed L. Abdel-Mawgood, Mohamed I. Motawei, Soleman Al-Otayk, Monther T. Sadder, Abdallah M. Elgorban, Hussein M. Migdadi, Khaled A. Moustafa and Abdullah A. Al-Doss

Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, Saudi Arabia
Plant Production Department, College of Food and Agriculture Sciences, King Saud University, Saudi Arabia
Plant Production and Protection Department, College of Agriculture and Veterinary Medicine, Qassim University, Saudi Arabia
Centere of Excellence in Biotechnology Research, King Saud University, Saudi Arabia

Abstract
The morphological and molecular characteristics of four cereal cyst nematode (Heterodera avenae) populations collected from the Qassim, Tabouk, Riyadh, and Hail regions, Saudi Arabia were comparatively investigated. A large number of soil samples were collected from a representative field (72 ha) in each region. The morphological and morphometric characteristics of the populations were determined. Morphometric data were subjected to multivariate canonical discriminant analysis to analyze the relationship between the studied populations and to identify the variables that show the highest multiple correlations with these populations. For molecular characterization, DNA was extracted and purified from five random white females from each population. The internal transcribed spacer (ITS1) regions were subjected to direct sequencing to study the diversity of these populations. Discriminant analysis of the morphometric traits indicated that the studied populations belong to one species (H. avenae). The ITS1 sequence alignments showed similarity between individuals, ranging from 87 to 99%. Based on the sequencing data, consensus parsimonious and maximum likelihood trees showed an overlap between the individuals of the four populations, suggesting that all four populations represented one species. However, based on the morphological and molecular analysis, the Hail population was somewhat different from the other three populations. Minor genetic and phenotypic differences between the four populations could indicate that these populations are heterogenic, probably mixed populations. This study also revealed the value of some J₂ morphometric traits such as J₂ midbody width, J₂ body width at the anus, J₂ head height and the J₂ ratios a, b, c and c' in determining intraspecific variation between H. avenae populations.

Pages 970-979 | Full Text PDF

Genetic diversity of rice cultivars by microsatellite markers tightly linked to cooking and eating quality

Narjes Tabkhkar, Babak Rabiei and Atefeh SabouriDepartment of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, P.O. Box: 41635-1314, University of Guilan, Rasht, Iran

Abstract
Improving cooking and eating quality of rice is one of the important objectives of many breeding programs. The study of genetic diversity in specific regions of rice genome using molecular markers is an important index that can be used for the application of marker assisted selection (MAS) in rice breeding programs. In this study, 48 rice genotypes were grouped using 7 microsatellite (SSR) markers tightly linked to major QTLs controlling three major components of rice cooking and eating quality (i.e. amylose content, gelatinization temperature and gel consistency). The number of polymorphic alleles produced by each microsatellite marker ranged from 3 alleles at RM314 locus to 10 alleles at RM276 locus. The total number of polymorphic alleles was 41 alleles with the average of 5.86 alleles per SSR locus. Effective number of alleles varied from 2.68 to 5.25 alleles at RM314 and RM276, respectively, with an average of 3.74 alleles per locus. The average heterozygosity based on Nei's gene diversity was 0.72 indicating high genetic variation among the studied varieties. Cluster analysis with UPGMA method based on simple matching (SM) similarity coefficient divided the genotypes into four groups and separated the landrace cultivars with good cooking and eating quality (based on Iranian taste) from others. Cophenetic correlation coefficient between similarity matrix and cophentic matrix was 0.93 indicating that the used similarity coefficient and cluster analysis method were suitable to use the information derived from markers to group rice genotypes. Results of this research indicated that microsatellite markers linked to genes or QTLs controlling grain cooking and eating properties are suitable tools for marker assisted selection (MAS) to identify rice grain quality.

Pages 980-985 | Full Text PDF | Supplementary data

Identification of quantitative trait loci for grain yield and its components in response to low nitrogen application in rice

Dong Wei, Kehui Cui, Junfeng Pan, Qiang Wang,Kai Wang, Xiaomei Zhang, Jing Xiang, Lixiao Nie, Jianliang Huang

National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
Rice Research Institute, Guangdong Academy of Agricultural Science, Guangzhou 510640, China
China National Rice Research Institute, Hangzhou 310006, China

Abstract
Increasing grain yield with high nitrogen (N) use efficiency and less N application is an important objective in rice genetic programs. A total of 127 rice recombinant inbred lines derived from Zhenshan 97 ´ Minghui 63 (Oryza sativa L.) were used for detecting the quantitative trait loci (QTLs) of grain yield and its components (panicle per m², spikelets per panicle, grain filling ratio, and 1000-grain weight) under low (LN) and normal nitrogen (NN) applications in 2006 and 2007. Among 68 QTLs detected across the two years under LN and NN, 33 QTLs were identified under LN (18 in 2006 and 15 in 2007), and 35 QTLs under NN (18 in 2006 and 17 in 2007). Only ten of 33 QTLs (30.3%) under LN and 14 of 35 QTLs (40%) under NN were detected simultaneously in both two years. A total of 18 of 36 QTLs (50%) in 2006 and 16 of 32 QTLs (50%) in 2007 were simultaneously detected under the two N applications, respectively. The results showed that environments over the two years and N applications had their significant effects of QTL expressions. The seven regions (RG532-G359-R753 on chromosome 1, RM53-R1738 on chromosome 2, RZ403-C1087- RG393 on chromosome 3, RM26-C246-C624 and C734b-RG360 on chromosome 5, R1440-C1023 and RZ471-RG678 on chromosome 7) were found to have their effects simultaneously under LN and NN in a year or two years. Eight regions were only detected under LN. Our results may provide information for genetically improving rice NUE by keeping yield stability by decreasing N application, and by increasing yield under current level of N application. Those regions that are stable across various nitrogen application and responsive to LN would be useful for improving grain yield formation with high N use efficiency and less N application in rice breeding.

986-994 | Full Text PDF

Comparative effects of two alkali stresses, Na₂CO₃ and NaHCO₃ on cell ionic balance, osmotic adjustment, pH, photosynthetic pigments and growth in oat (Avena sativa L.)

Zhan-Wu Gao, Ji-Tao Zhang, Zhuang Liu, Qing-Tao Xu, Xiu-Jun Li and Chun-Sheng Mu

Baicheng Normal University, Department of Geography, Baicheng 137000, China
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, China
Baicheng City Academy of Agriculture Sciences, Ji Lin Province Research Institute of Sunflower, 137000, China
Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology of Ministry of Education, Changchun 130024, Jilin Province, China

Abstract
This study examines the comparative effects of NaHCO₃ and Na₂CO₃ on young oat (Avena sativa L.) plants to elucidate the species’ physiological adaptive mechanisms to alkali stress. Factors considered are the intracellular influx and efflux of ions, ionic balance, osmotic adjustment, pH homeostasis, photosynthetic pigments and growth. Results show that, Na₂CO₃ had stronger effects than NaHCO₃, and that with increasing concentrations of both stresses the plant showed rising Na⁺influxes into the shoot resulting in Na⁺ ion toxicity. This is tolerated by Na⁺ sequestration in the vacuole; the accumulation mainly of Cl^-, SO₄^2- and the synthesis of high concentrations of organic anions to maintain vacuolar ionic balanceand,lastly by the synthesis of proline in the cytoplasm to avoid dehydration. Moreover, Na₂CO₃ stress inhibits growth more strongly, compared to NaHCO_3,because of the higher energy costs associated with Na⁺ exclusion and compartmentalisation,the syntheses of organic anions, the syntheses of proline in the cytoplasm, reduced photosynthetic capacity and increased membrane permeability. Compared to the shoot, although the root had a similar response to both stresses, it showed a higher tolerance because high Na₂CO₃ stresses (>48 mmol L^-1) resulted in significant increases in root tissue pH, but did not affect the pH homeostasis of the shoot. Additionally, while both stresses decreased root dry weight, they did not significantly affect root extension growth. This indicates that oat adopts an opportunistic guerrilla strategy by which it avoids resource-poor patches of soil (e.g. high alkali) while preferentially exploiting more favorable habitats by maintaining root extension.

Pages 995-1003 | Full Text PDF

Research Note

Optimization of factors for efficient isolation of protoplasts in sunflower (Helianthus annuus L.)

C. Kativat, O. Poolsawat, P. Tantasawat

Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand
Center of Excellence on Agricultural Biotechnology: (AG-BIO/PERDO-CHE), Bangkok 10900, Thailand

Abstract
Various factors influencing the efficiency of sunflower protoplast isolation including genotypes (10A and PI 441983), tissue types (young leaves and hypocotyls), isolation methods (M1-M5) and cellulase concentrations (0.1, 0.5, 1.0 and 1.5%) were evaluated to obtain optimum protoplast isolation procedures. Young leaves were preferable to hypocotyls in production of viable protoplasts. Genotypes and isolation methods significantly affected both yields and viability of protoplasts from both tissues. Moreover, protoplast yield from leaf tissues was also influenced by cellulase concentrations. Using hypocotyls as explants, 10A line gave the highest number of viable protoplasts (4.24 × 10⁶protoplasts/ g fresh weight [FW]) when incubated at 25°C for 16 h in the optimal isolation solution containing 1% cellulase and 0.5% macerozyme. Higher number of viable protoplasts observed in this genotype, compared to PI 441983, may result from differences in hypocotyl morphology between the two genotypes. By contrast, for leaf explants the highest numbers of viable protoplasts, 6.13 × 10⁶ protoplasts/ g FW for 10A line and 8.81 × 10⁶ protoplasts/ g FW for PI 441983 line, were achieved when incubated with 0.1 and 0.5% cellulase, respectively, in the optimal isolation solution containing 0.05% driselase, 0.02% macerozyme and 0.1% bovine serum albumin (BSA) at 25°C for 16 h. These results suggest that suitable sunflower protoplast isolation procedures varied according to genotypes and tissue types, and need to be individually optimized.

Pages 1004-1010 | Full Text PDF

Variations in high-molecular-weight glutenin subunits in the main wheat growing zones in China

Jun Ji, Xiaoli Guo, Fa Cui, Dongcheng Liu, Jiazhu Sun, Wei Zhang, Aimin Zhang_, Junming Li

Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, 050021, P. R. China
College of Biology, China Agricultural University, Beijing 100193, P. R. China
The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, P. R. China

Abstract
Variations in high-molecular-weight glutenin subunits (HMW-GS) at the Glu-1 loci were studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method among 1942 advanced lines and cultivars from eight wheat-growing zones in China. There were 26 alleles and 83 types of HMW-GS composition detected, including some interesting and unique alleles and allelic compositions. Among the 26 alleles, the most frequent HMW-GS alleles were null at the Glu-A1 locus, 7+8 and 7+9 at the Glu-B1 locus, and 2+12 at the Glu-D1 locus. The HMW-GS compositions N, 7+8, 2+12 and N, 7+9, as well as 2+12 more frequently occurred than others among the 1942 wheat cultivars and advanced lines. The results can provide useful information for breeding programmes to improve bread-making quality and develop new cultivars.

Pages 1011-1016 | Full Text PDF

Using different aspects of stability concepts for interpreting genotype by environment interaction of some lentil genotypes

Rahmatollah Karimizadeh, Mohtasham Mohammadi, Naser Sabaghnia and Mohammad Kazem Shefazadeh
Dryland Agricultural Research Institute (DARI), Gachsaran, Iran
Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Maragheh, Maragheh, Iran
Department of Agronomy, Yasooj Branch, Islamic Azad University, Yasooj, Iran

Abstract
Multi-environmental tests were done for variety recommendation in the final stages of breeding programs for awareness of the importance of genotype × environment (GE) interactions. Sixteen genetically improved lentil genotypes and two cultivars were grown in 12 semiarid environments in Iran during 2007 to 2009. Results of combined ANOVA showed there were significant GE interactions and that genotypes varied significantly for seed yield. According to environmental variance and coefficient of variation statistics Type I, genotypes G7, G8 and G11 were the most stable genotypes while based on four parameters, which used GE magnitude, genotypes G5, G13 and G18 were the most stable. Results of the principal component (PC) analysis and correlation analysis of different stability concepts (Type I to Type IV) and seed yield indicated that only the Type II stability method would be useful for simultaneous selection for high yield and stability. The most favorable genotypes for a given environment were assessed by considering high mean yield, Type II stability and variance of years within a location for each test location, so genotypes G5 and G12 for Gorgan, genotypes G1 and G12 for Moghan, genotypes G2 and G12 for Lorestan and genotypes G1, G5, G14 and G15 for Gachsaran could be recommended for commercial release in rain-fed areas.

Pages 1017-1023 | Full Text PDF

Effects of macropore continuity on water movement and solute transport in a loessial soil

B.B. Zhou, S. Li , Q.J. Wang, Y.L. Jiang, Y. Li

Institute of Water Resources and Hydro-electric Engineering, Xi’an University of Technology, Xi’an, 710048, China
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Northwest A & F University Yangling 712100, Shaanxi, China

Abstract
Flow through macropores, created by soil pedogenesis and biological activity, play important roles in soil water and chemical transport on the Loess Plateau. Numerous studies have examined individual macropores and the effects of their size on solute transport, but few have assessed the effects of macropore continuity and of neighboring macropores. This paper describes a laboratory investigation of the effects of macropores with varying degrees and types of continuity on the transport and distribution of solutes in loessial soil columns. Soil columns (2-D, 60 cm high) containing standardized artificial macropores were used to obtain breakthrough curves (BTCs) for input solutions containing 1190 mg/L KBr, and 100 mg/L FD&C Blue #1 (a food dye) under a constant hydraulic head of 8 cm. The types of macropore were: open at both the surface and bottom of the soil column (O-O); open at the surface-closed at the bottom (O-C); and closed at the surface-open at the bottom (C-O). Columns with no macropores served as a control. As expected, in the O-O column the solution reached the bottom rapidly, bypassing most of the soil matrix. The presence of an O-C macropore resulted in weak retardation and much deeper penetration of the bromide and FD&C Blue #1 than in the control columns, but the C-O macropore had little effect on either BTCs or solute distributions. In further tests where neighboring macropores were present, an inclined macropore strongly affected solute concentrations in the profile. Therefore, the type of macropore and the presence of neighboring macropores, all affect soil water flows and solute infiltration parameters.

Pages 1024-1029 | Full Text PDF

Combining ability analysis and evaluation of heterosis in Jatropha curcas (L)

Alireza Biabani, M. Y. Rafii, Ghizan Saleh, Mahmoodreza Shabanimofrad, M.A. Latif
Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia (UPM), 43400 UPM Serdang, Selangor, Malaysia
Institute of Tropical Agriculrure (ITA), Universiti Putra Malaysia (UPM), 43400 UPM Serdang, Selangor, Malaysia

Abstract
With the aim of estimating genetic parameters and recognizing superior Jatropha curcas combinations, ten superior plants were selected based on seed yield and oil content, and were crossed among them in a 10 x 10 half-diallel mating design to produce 45 F₁-hybrids. The experiment was conducted in nursery stage using a randomized complete block design (RCBD) with three replications. Analysis of variance for the combining ability indicated that GCA and SCA variance were significant at 1% probability for plant height, collar diameter and number of leaves in nursery stage. The low ratio of GCA/SCA exhibited the non-additive effects. Broad sense heritabilies were high for plant height, collar diameter and number of leaves. Estimates for narrow sense heritability of the traits , plant height collar diameter and number of leaves were low. Percentages of heterosis and heterobeltiosis values for plant height, collar diameter and number of leaves ranged from negative to positive. This showed that the existence of dominance or non-additive gene actions might be present in the hybrids. On the basis GCA and SCA effects, parents, Ph1.2 and In2.1 and hybrids Ph1.2 (3) × In1.2 (8), Ph1.1 (9) × My2.2 (10) and My2.1 (1)× My2.2 (10) could be used for future breeding program.

Pages 1030-1036 | Full Text PDF | Supplementary data

Isolation and molecular characterization of wheat (Triticum aestivum) Dehydration Responsive Element Binding Factor (DREB) isoforms

Sima Sazegari, Ali Niazi

Institute of Biotechnology, Shiraz University, Shiraz, Iran

Abstract
Due to adverse effects of abiotic stresses on plant growth and development, we focused on an effective abiotic stress responsive element known as Dehydration responsive element binding factor (DREB) in Triticum aestivum. The objective of the research was to isolate and molecularly characterize two wheat DREB2 (WDREB2) gene isoforms. In order to isolate WDREB2 isoforms, plants were exposed to cold stress. Total RNA was extracted from cold-treated plant leaves and first-strand cDNA was synthesized. Two isoforms were isolated by specific primers and submitted in NCBI database (Accession No. JQ004969 and HQ171443). Searching for similar sequences to isolated isoforms by NCBI BLASTn resulted in 10 sequences in Triticum aestivum with = 95% identity and = 90% coverage. Multiple alignments on homologous sequences were preformed. The results showed that all these homologous sequences are related to one definite gene, WDREB2, which has 3 different alternate spliced forms or isoforms. ß Isoform that lacks transcription activation domain is inactive while a is an active isoform. In order to verify a isoform activity, WDREB2 a isoform was expressed in tomato using Agrobacterium mediated transformation and a isoform-expressed plants were tested. Phonotypical comparison between transgenic and normal plants under cold stress confirmed the activity of WDREB2a isoform. In addition to laboratory research, 2 available sequences, submitted as wheat DREB gene promoter (Accession No GU785009 and GU785008) were selected and promoter analysis was carried out. Several motif sites such as ABRE, C-repeat/DRE and MBS, which are important Cis acting elements in abiotic stresses response were identified.

Pages 1037-1044 | Full Text PDF

Molecular cloning and characterization of two isoforms of cytoplasmic/mitochondrial type NADPH-dependent thioredoxin reductase from rice (Oryza sativa L. ssp. indica)

Hedieh Eslampanah, Azar ShahpiriDepartment of Agricultural Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan-84156-83111, Iran

Abstract
An NADP/thioredoxin system, consisting of NADPH, NADPH-dependent thioredoxin reductase (NTR) and thioredoxin (Trx) plays a post-translational regulatory role by reducing disulfide bonds in target proteins involved in various cellular processes. Plants have a complex NTR/Trx system comprising several Trxs and NTR isoforms. Three genes encoding NTR were found in the genome of rice. OsNTRC is chloroplastic type NTR whereas OsNTRA and OsNTRB are cytoplasmic/mitochondrial type NTR. The presence of two isoforms of cytoplasmic/mitochondrial type NTR with high amino acid identity raises the question of their functional specificity. In the present study, we describe isolation and cloning of two cDNAs encoding OsNTRA and OsNTRB. Both isoforms were heterologously expressed in Escherichia coli and purified using affinity chromatography, enabling comparison of their NADPH-dependent reduction activities. OsNTRB and OsNTRA exhibited almost similar in vitro activities. OsNTRB was highly expressed in roots and shoots of one, two and three week-old rice seedlings, whereas the expression of OsNTRA in shoots was much higher than roots. Differential expression of OsNTRA in different tissues suggests that this isoform may have different functions in different tissues.

Pages 1045-1050 | Full Text PDF

Relationship between air temperature and degreening of lemon (Citrus lemon L. Burm. f.) peel color during maturation

Javier Manera, José M. Brotons, Agustín Conesa, Ignacio Porras

Department of Physics and Architecture of Computers, Miguel Hernández University, Ctra de Beniel, km 3.2. 03312 Orihuela, Spain
Department of Economic and Financial Studies, Miguel Hernández University, Avda. de la Universidad, s/n, 03202. Elche. Alicante, Spain
Department of Vegetable Production and Microbiology, Miguel Hernández University, Ctra de Beniel, km 3.2. 03312 Orihuela. Alicante, Spain
Department of Citriculture, Murcian Institute of Agriculture and Food Research and Development (IMIDA). Estación Sericícola. Calle Mayor s/n. 30150. La Alberca, Spain

Abstract
This study describes the relationship between air temperature and the loss of greenness in lemon peel and the appearance of the typical yellow color in the lemon varieties Eureka Frost, Lisbon Frost and the Fino 49, all on Citrus macrophylla rootstock. The change in the colorimetric coordinate ´a´ was studied, and the hue angle and chroma were calculated to ascertain the influence of temperature on these parameters. The study covered six campaigns (2003-2009), with measurements being made every week or fortnight in 10 fruit per tree and 4 trees per variety. The results show that the values of the colorimetric coordinate a (of the HunterLab) was most closely correlated with the mean of the minimum daily temperature of the 21 days prior to the measurement (adjusted R² >0.93). Identical results were obtained for Chroma and hue angle. It was determined that the color of the peel begins to change from green to yellow when the minimum temperature falls below 15 ºC, reaching full “lemon yellow” below 6 ºC. This means that in areas where mean minimum temperatures do not reach 15 ºC for 21 consecutive days natural degreening will not occur. As a consequence, artificial degreening, with the increased expense that this entails for the crop, will be necessary. The knowledge gained with this study will be of interest for determining the suitability of areas of the world where lemon tree plantations are being considered, so that prospective growers will not have to resort to artificial degreening.

Pages 1051-1058 | Full Text PDF

Response of King of Bitters (Andrographis paniculata Nees.) seedlings to salinity stress beyond the salt tolerance threshold

Daryush Talei, Mohd Khanif Yusop, Mihdzar Abdul Kadir, Mohd puad Abdullah and Alireza Valdiani
Department of Cell and Molecular Biology, Faculty of Biotechnology & Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
Medicinal Plant Research Centre, Shahed University, Tehran, Iran
Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor DE, MalaysiaDepartment of Agriculture technology, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor DE, Malaysia

Abstract
Salt tolerance threshold is an important factor for screening salt tolerant plants in the selection process. The objectives of present study were to determine the salt tolerance threshold and to evaluate the six accessions of Andrographis paniculata for salt tolerance. Two experiments were carried out for this purpose. In first experiment, 40-day-old seedlings were grown at different salinity levels (control, 4, 8, 12 and 16 ds m^-1) on Hoagland medium and compared at various exposure times (0, 5, 10, 15 and 20 days). The results indicated that salinity, exposure time and their interactions had significant effect on the morphologic and agronomic traits. The relative growth rate (RGR) during exposure time was significantly decreased in two stages. The initial decrease happened five days after salt exposure, mainly due to osmotic stress, while the secondary reduce occurred 15 days after salt exposure because of ion stress. The results revealed no significant differences among accessions based on salt tolerance index in first ten days. All the studied morphological traits were decreased with increasing salinity levels. Finally, it was realized that 12 ds m^-1 salinity for a period of 15 days can be considered as the salt tolerance threshold for A. paniculata seedlings. In the second experiment 32 different accessions were evaluated under salinity stress. All measured Agro-morphological traits; chlorophyll content, K⁺and Ca²⁺ content were significantly decreased with increasing salinity levels, while proline and Na⁺ content increased. Under salinity stress, tolerant accessions could accumulate higher proline, K⁺and Ca²⁺, and lower Na⁺content than sensitive accessions. Consequently, the results suggest that proline, Na⁺, K⁺ and Ca²⁺ are the most effective indicators for salinity tolerance screening in A. paniculata.

Pages 1059-1067 | Full Text PDF

Assessment of genetic variation of genus Salvia by RAPD and ISSR markers

Zahra Sepehry Javan, Fatemeh Rahmani, Reza Heidari

Department of Biology, Faculty of Science, Urmia University, Urmia, Iran
Institute of Biotechnology, Urmia University, Urmia, Iran

Abstract
RAPD and ISSR markers were used to evaluate the genetic variation among eight species of Salvia collected from different locations of Ardebil in Iran. Fifteen RAPD primers produced 220 scorable electrophoretic bands which all were polymorphic. Fifteen ISSR primers also produced 245 amplified bands of which 241 were polymorphic. The pair-wise Jaccard genetic similarity varied from 0.0725 to 0.3529 for RAPD and from 0.1692 to 0.3478 for ISSR data. The dendrogram was constructed using UPGMA method with the help of NTSYSpc 2.02 software, which distinguished five and four main groups among eight species of Salvia based on RAPD and ISSR analyses, respectively. In the present study, detected polymorphism level represents high genetic distance at inter-species level and introduces the RAPD and ISSR as efficient markers for genetic relatedness assessment in Salvia. Furthermore, our genetic diversity analysis could provide useful information for utilization of these materials, especially for genetic improvement.

Pages 1068-1073 | Full Text PDF

GGE biplot analysis of genotype × environment interaction in wheat-barley disomic addition lines

Ezatollah Farshadfar, Reza Mohammadi, Mostafa Aghaee, Zahra Vaisi
College of Agriculture, Razi University, Kermanshah, Iran
Seed and Plant Improvement Institute, Karaj, Iran
Department of Plant Breeding, Islamic Azad University, Kermanshah branch, Kermanshah, Iran

Abstract
Identification of the genetic architecture of phenotypic stability and management of adaptational genes are prerequisites for improvement of plant adaptation. To locate the genes controlling adaptation in barley, wheat-barley disomic addition lines were used in a randomized complete block design with three replications under rainfed and irrigated conditions for three consecutive cropping seasons (2009-2011). The GGE [genotype main effect (G) and genotype by environment interaction (GE)] biplot graphical tool was applied to analyze multi-environment trials (MET) data. Combined analysis of variance showed that the GE interaction effect accounted for 57.3% of total variation, indicating that the GE interaction is more complex. The first two principal components (PC1 and PC2) were used to display a two-dimensional GGE biplot. Thus, genotypic PC1 scores >0 classified the high yielding genotypes while PC1 scores <0 identified low yielding genotypes. Unlike genotypic PC1, genotypic PC2 scores near zero exhibited stable genotypes whereas large PC2 scores discriminated the unstable ones. The GGE biplot analysis was useful in identifying stable genotypes with high yield performance. Disomic addition line (DAL) H7, was characterized as genotype with the highest mean yield and low stability. In contrast, DAL H2, was identified as the best genotype in integrating mean yield with the highest stability performance. It was concluded that most of the genes controlling yield and yield stability in barley are located on chromosome H2.

Pages 1074-1079 | Full Text PDF

Experimental studies on the transport of copper down the soil profile and in runoff during rainfall

Wencai Dong, Quanjiu Wang
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling, Shaanxi 712100, China
Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Institute of Water Resources, Xi an University Technology, Xi an, Shannxi, 710048, China

Abstract
The widespread use of fertilizers that contain copper have led to concern about the contamination of groundwater. The vertical movement of labile copper down the soil profile has been studied by many researchers. Little research, though, has investigated the mobility of copper in runoff during rainfall. Laboratory experiments were conducted to determine the distribution and transport of copper down the soil profile and in the runoff under conditions of simulated rainfall. Two soils (loam and sandy loam), three initial soil-moisture contents (5%, 15%, and 20%, measured gravimetrically) and three intensities of rainfall (60, 96, and 129 mm h^-1) were used to evaluate the effects of these variables and their interactions on the movement of copper vertically down the soil profile and horizontally in runoff. The results indicated that the transport of copper into runoff and movement with the runoff from rainfall was affected by the soil type, soil-moisture content, and intensity of rainfall. The mean copper-ion content in the runoff from the sandy loam was 1.25 times greater than that observed from the loam, increased 0.436 times when the soil-moisture content increased 5% between 5% and 20%, and increased 0.64 times when the intensity of rainfall increased 30 mm h^-1 between 60 mm h^-1 and 129 mm h^-1. The results from this study show that copper enters and is transported by the runoff from rainfall. The prolonged application of fertilizers containing copper may thus pose an environmental risk.

Pages 1080-1087 | Full Text PDF

Genetic diversity and taxonomic relationships of some Ipomoea species based on analysis of RAPD-PCR and SDS-PAGE of seed proteins

Kadry Abdel Khalik, Gamal Osman and Waeil Al-Amoudi
Biology Department, Faculty of Science, Umm-Al-Qura University, Mecca 673, Saudi Arabia
Botany Department, Faculty of Science, Sohag University, Sohag 82524, Egypt
Agricultural Genetic Engineering Research Institute (AGERI)-Giza, Egypt

Abstract
To elucidate the genetic diversity of ten Ipomoea species, seed proteins were analyzed by SDS-PAGE and RAPD analysis. According to SDS-PAGE analysis, in total 51 different bands were identified across the studied species. The number of bands varies from 16 bands in Ipomoea cairica, to 3 bands in I. sinensis. The similarity analysis based on the SDS-PAGE profile turned out to be a useful character for the inequity of Ipomoea species both on the subgeneric and sectional level. Analysis of RAPD-PCR of DNA provided more precise information concerning relationships between Ipomoea sections than SDS-PAGE analysis. A remarkable result from this study was identifying a close relationship between Ipomoea purpurea of section Pharbitis (subgenus Ipomoea) and species of the subgenus Quamoclit. Further support comes from the molecular data of RAPD which indicate that Ipomoea cairica should be considered a well separated section which may be related to section Orthipomoea. Our results suggest that section Erpipomoea is not a monophyletic group, whereas species of section Orthipomoea form a single monophyletic section.

Pages 1088-1093 | Full Text PDF | Supplementary data

An efficient Agrobacterium tumefaciens -mediated genetic transformation of bitter melon (Momordica charantia L.)

M. Thiruvengadam, N. Praveen, I.M. Chung
Department of Applied Life Science, Konkuk University, Seoul 143-701, South Korea

Abstract
A simple and efficient protocol for Agrobacterium tumefaciens-mediated genetic transformation of bitter melon (Momordica charantia L.) has been developed. Pre-cultured leaf explants were transformed by co-cultivation with Agrobacterium tumefaciens strain LBA4404 harbouring a binary vector pBAL2 carrying the reporter gene ß-glucuronidase intron (gus) and the marker gene neomycin phosphotransferase (nptII). After co-cultivation, explants were transferred in to a callus induction medium containing 7.7 µM naphthaleneacetic acid (NAA) with 2.2 µM thidiazuron (TDZ), 100 mg L^-1 kanamycin and 300 mg L^-1 carbenicillin. Regeneration of adventitious shoots from callus was achieved on MS medium containing 5.5 µM TDZ, 2.2 µM NAA, 3.3 µM AgNO_3,100 mg L^-1 kanamycin and 300 mg L^-1 carbenicillin. Transgenic shoots were excised from callus and elongated in MS medium fortified with 3.5 µM GA₃,100 mg L^-1 kanamycin and 300 mg L^-1 carbenicillin. The transgenic elongated shoots were rooted in MS medium supplemented with 4.0 µM IBA and 100 mg L^-1 kanamycin. The putative transgenic plants were acclimatized in the greenhouse and seeds were subsequently collected from mature fruits. Further, the presence of acetosyringone (300 µM) in the co-cultivation medium, infection of explants for 30 min and 3 days of co-cultivation proved to be critical factors for greatly improving the transformation efficiency. Histochemical GUS assay and polymerase chain reaction of field-established transgenic plants and their offspring confirmed the presence of the gus and nptII genes, respectively. Integration of T-DNA into the genome of putative transgenics was further confirmed by Southern blot analysis. The nptII gene expression in transgenic plants was confirmed by RT-PCR. A transformation efficiency of 7% was obtained.

Pages 1094-1100 | Full Text PDF

Influence of phosphate bio-fertilizer on quantity and quality features of marigold (Tagetes erecta L.)

Davood Hashemabadi, Fatemeh Zaredost, Maryam Barari Ziyabari, Mohammad Zarchini, Behzad Kaviani, Maryam Jadid Solimandarabi, Ali Mohammadi Torkashvand, Somayeh Zarchini Department of Horticultural Science, Rasht Branch, Islamic Azad University, Rasht, Iran
Young Researchers Club, Rasht Branch, Islamic Azad University, Rasht, Iran
Management Group, Hafez Khak Gil Company, Iran
Islamic Azad University, Tafresh Branch, Tafresh, Iran

Abstract
The present investigation was conducted to study the effect of bio-fertilizer (Barvar-2) and phosphorus on quantity and quality characteristics of marigold (Tagetes erecta L.). A factorial experiment based on randomized complete blocks design (RCBD) with three replications was carried out with two factors including methods of bio-fertilizer (Barvar-2) application (without bio-fertilizer inoculation, seed inoculation, root inoculation and seed plus root inoculation), and different levels of chemical phosphorus (100, 200, 300 and 400 mg l^-1). In the present study, plant height, the number of leaf per plant, shoot fresh weight, shoot dry matter percentage, the content of total phosphorus of cultivation media and shoot and flower diameter were measured. Results revealed that the application of bio-fertilizer and phosphorus was significant on most characters in 1% probability level. The interaction effect of bio-fertilizer and phosphorus was not significant on studied characters except for total shoot phosphorus and the number of leaf per plant. The best plant height (26.87 cm), the number of leaf per plant (56.27), flower diameter (84.420 mm), shoot fresh weight (19.94 g) and total shoot phosphorus (0.353%) was obtained under inoculation of seeds and roots with bio-fertilizer × 400 mg l^-1 phosphorus. Maximum of shoot dry matter (19.86%) and total medium phosphorus (0.235%) was calculated in treatments of 200 mg l^-1 phosphorus without bio-fertilizer inoculation and 200 mg l^-1 phosphorus with seed inoculation, respectively.

Pages 1101-1109 | Full Text PDF

Effects of cultivar on rodent damage in Australian macadamia orchards

James Eldridge, Matthew Whitehouse, David Elmouttie, and Grant Hamilton

Discipline of Biogeosciences, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia

Abstract
The Black rat (Rattus rattus), a serious pest of Australian macadamia orchards has been estimated to cause up to 30% crop damage in Australian orchards. In recent years an increase in the number of commercially available cultivars has seen a change in orchard characteristics in Australia, primarily effecting fruiting and flowering patterns. This has been suggested to affect the feeding behaviour of rodents and in turn altered the damage process. In this study we compare the extent of damage in orchards containing one of three prevalent cultivars (A4/A16, A268 and HAES 344/741) and investigate the influence of these cultivars, particularly their distinctive fruiting traits, on rodent damage within the orchard. We demonstrate that the temporal pattern and extent of damage differs between cultivar types. Newer Australian macadamia cultivars tested in this study were found to be far more susceptible to rodent damage than the older Hawaiian developed cultivars, most likely due to an extended fruiting period and thinner shells. This has resulted in a more sustained period of crop damage than the patterns of crop damage observed in previous Australian studies. Crop damage caused by R. rattus is significantly higher in orchards that maintain high levels of canopy resources through the fruiting season and we postulate that this is due to the extended fruiting periods of the new cultivars used. The maintenance of canopy resource load in turn corresponds to high crop damage, in this study resulting in crop losses of up to 25%.

Pages 1110-1115 | Full Text PDF

Accuracy and precision of some methods in producing soil erosion maps

Ali Mohammadi Torkashvand and Behzad Kaviani

Department of Horticultural Science, Rasht Branch, Islamic Azad University, Rasht, Iran

Abstract

Soil conservation is one of the most strategies for sustainable production of crops. Erosion types mapping is one of the most important and basic methods in erosion and sediment yield studies to determine suitable soil conservation programs. In this study, some methodologies were compared in providing maps of erosion features, in research which took place in the Roodbar basin, Guilan province, Iran at a scale of 1:250,000. The accuracy and precision of three metods were evaluated in producing erosion map types including (A) Integration of land units, rocks erodibility, height and climate layers; (B) Integration of land use, land units, rocks erodibility, height and climate layers; and (C) A photomorphic unit map produced from processed satellite images. Since the large area of basin has been covered by dense forest, therefore, the accuracy and precision of models were investigated in two methods; with considering forest land use, and without considering forest land use. The greatest accuracy is related to image processing in producing erosion types maps that the difference of accuracy between two models (with and without forest land use) in producing maps of surface, rill, gully and erosion features was 10.1%, 8.5%, 14.2% and 20.1%, respectively. Comparison of ground truth maps of erosion types and working unit maps indicated that the satellite image photomorphic units map provide the best method in producing erosion types maps. It is suggested that satellite images with higher resolution and integration of other layers, such as soil, be investigated to improve accuracy further.

Pages 1116-1122 | Full Text PDF

Evaluation of flag leaf chlorophyll content index in 30 spring wheat genotypes under three irrigation regimes

Ping LI, Pute WU and Jianli CHEN
College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling, Shaanxi, China 712100
National Engineering Research Center for Water Saving Irrigation at Yangling, Yangling, Shaanxi, China 712100
Department of Plant Soil and Entomological Sciences, University of Idaho, 1691 S. 2700 W. Aberdeen, ID, USA 83210
Abstract
The chlorophyll content in flag leaves reflects photosynthetic activity and yield potential of wheat plants. A two-year field experiment was carried out to evaluate flag leaf chlorophyll content index (CCI) at different growth stages [Feekes 10.5.2 (anthesis), Feekes 11.1 (kernels milky ripe, GF-1), and Feekes 11.2 (kernels mealy ripe, GF-2)] and irrigation regimes [non-irrigated, 50%-evapotranspiration (ET) irrigated, and 100%-ET irrigated] in 30 spring wheat genotypes. The CCI of four groups with different yield performances across irrigation regimes: high-yield genotype (HYG), low-yield genotype (LYG), drought-resistant genotype (DRG) and drought-susceptible genotype (DSG), were compared. Maximum flag leaf CCI was recorded at GF-1 stage for most genotypes under all irrigation regimes. Severe drought stress decreased CCI value while both severe and moderate drought stress accelerated the CCI loss after GF-1 stage. No correlation between CCI and grain yield was found, but CCI decrease (CCID) and grain yield was negatively correlated (P < 0.05), especially for the well-watered condition. Compared with the other groups, DRG had much higher CCI, especially CCI evaluated at anthesis under well-watered condition; the CCI of HYG declined either later or slower after GF-1 stage. Results from this study suggest that GF-1 stage may be the optimum time for evaluating flag leaf CCI; the CCID from GF-1 to GF-2 rather than the CCI value could be used as an index to predict grain yield; the CCI value may be considered as an indicator for screening drought resistant genotypes in wheat breeding programs.

Pages 1123-1130 | Full Text PDF

Association analysis of important agronomical traits of maize inbred lines with SSRs

Qianqian Zhang,Chenglai Wu,Fengyang Ren, Yan Li,Chunqing Zhang

State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an 271018 Shandong, China

Abstract
The genetic markers of important traits are evaluated in order to improve the maize inbred lines. Ninety-four maize inbred lines were used to assess the genetic and phenotypic diversity and make association analysis of 26 agronomical traits with 204 genome-wide SSR markers, which were divided into five subpopulations by a model based population structure analysis. The population consisted of 94 maize inbred lines, presented high genetic diversity and significant linkage disequilibrium (LD), and could be used in the detection of genome-wide SSR marker-phenotype association. Although a total of 106 loci were associated with the trait of the mean results of two years at P<0.01 level, thirty-nine association loci were detected with an MLM association analysis model to existing significant association (P<0.05) with 17 traits in two years, simultaneously, in which there were three loci associated with PH, four loci with AD, five loci with KRN, three loci with HKW, etc. Five association loci were new discovery, which were bnlg2162, bnlg1118, phi077, umc1161 with BYC, and bnlg1118 with GLN. The strongest association loci were umc1917 with AD and HKW (P<0.01), umc2025 with CD (P<0.0001), etc. The number of associated loci detected on chromosome 1 was thirteen, which was more than chromosome 2 and 5(5), and more than chromosome 4(4), etc. The above results were useful for genetic improvement and molecular maker-assisted breeding in maize.

Pages 1131-1138 | Full Text PDF | Supplementary data