September 2009

Modeling biomass allocation and grain yield in bread and durum wheat under abiotic stress

Abdullah A. Jaradat*¹
¹USDA-Agricultural Research Service, 803 Iowa Ave., Morris, MN 56267, USA

*Corresponding author: abdullah.jaradat@ars.usda.gov

Abstract

Differences between two wheat genotypes [ Triticum aestivum and T. durum species (A and D, respectively)] in dry matter (DM) partitioning into stems, leaves and spikes, in response to multiple abiotic stresses were quantified during two years of contrasting rainfall regimes. The impact of normal (N, ~1830 accumulated growing degree days, GDD), and late (L, ~1750 GDD) planting, in combination with normal (450 live seed m^-2) or large (25% above normal) population density on 1000-kernel weight (TKWT), kernels m^-2 (K m^-2), and grain yield (GY, Mg ha^-1) was quantified. Years, species, stress treatments, and their interactions explained 67, 73, and 75% of total variance in DM partitioned into stem (R-Stem), leaves (R-Leaves), and spike (R-Spike), respectively, 15 days after anthesis; and 50, 78 and 51% of variance in kernels m^-2, TKWT and GY, respectively, at physiological maturity. The two sets of variables were positively correlated (canonical r=0.90; p<0.0001); however, simple correlation coefficients between individual variables of both sets shifted in magnitude and significance in response to stress treatments. Partial least squares regression models were developed for each wheat species to quantify its response to stress.

Key words: Abiotic stress; Dry matter partitioning; models; wheat.

(Pages 237-248) PDF Text

Stability analysis of elite chickpea genotypes tested under diverse environments

Babar Manzoor Atta* and Tariq Mahmud Shah

Plant Breeding & Genetics Division, Nuclear Institute for Agriculture and Biology (NIAB),
P.O. Box 128, Jhang road, Faisalabad, Pakistan.

*Corresponding author: babar_niab@hotmail.com

Abstract

Twelve elite chickpea genotypes along with two check varieties were grown at four diverse locations in Punjab province to check their stability. The analysis of variance for seed yield at individual locations showed significant to highly significant differences between genotypes. Pooled analysis of variance over locations displayed highly significant differences between genotypes, locations and genotype x location interaction. Among 14 genotypes, the maximum mean seed yield over the locations was produced by the CC119/00 (1.229 t ha^-1) and the highest mean seed yield producing location was NIAB (1.412 t ha^-1). The cluster analysis effectively grouped the locations and genotypes into three clusters each viz. low, medium and high yielding ones. G x E interaction was of crossover in nature. Partitioning of total variance revealed significant differences among environments and genotypes for grain yield demonstrating the presence of considerable variations among genotypes as well as diversity of environments at various locations. The analysis of stability based on mean grain yield, regression coefficient and deviation from regression revealed that the genotypes; CC119/00, CC117/00 (Colchicine mutants), CM256/99, CH38/00 and K-70022 were most stable and adapted to the diverse environmental conditions of Punjab. Previously colchicine was only known to cause chromosome doubling but now it is also known to induce mutations. This is the first report of the systematic work on the mutants induced through colchicine treatments and demonstrated their yield superiority and stability over the locations. These genotypes are recommended for commercial cultivation and can also be effectively utilized in the recombination breeding programs to enhance genetic variability in kabuli chickpea.

Key words: Cicer arietinum L.; Cluster analysis; Colchicine; G x E interaction; Mutant; Seed yield; Stability

(Pages 249-256) PDF Text

Glycinebetaine and ascorbic acid can alleviate the harmful effects of NaCl salinity in
sweet pepper

Khafagy M. A, Arafa A. A and El-Banna M.F

Agriculture Botany Department. Faculty of Agriculture, Mansoura University, Mansoura, Egypt

Abstract

Salinity stress decreased plant height, root length, fresh and dry weights of shoot, chlorophyll concentration, as well as K⁺ concentration as compared to control. While, Na⁺ concentration was increased. Low salinity level 1500 ppm (4.84 dSm^-1) increased plant height and chlorophyll a concentration. High reduction in this parameters occurred under high salinity level 6000 ppm NaCl (11.88 dSm^-1). Pre-soaking of sweet pepper seeds in either glycinebetaine or ascorbic acid partially counteracted the harmful effect of NaCl salinity. Low salinity level increased thickness of either midrib region or leaf blade (palisade and spongy parenchyma) as well as the main vascular bundle dimensions. Whereas, moderate and high salinity levels led to a decrease in these parameters. Pre-treatment with glycinebetaine or ascorbic acid mitigated the affect of salinity on thickness of the midrib region and mesophyll tissue of leaf blade. However, all studied anatomical characters were increased as compared to untreated plants grown under such salinity levels.

Key words: Antioxidants, Capsicum annuum, leaf structure, osmoregulators, salt stress, seed germination.

(Pages 257-267) PDF Text

Pre-exposure to gamma rays alleviates the harmful effect of drought on the
embryo-derived rice calli

Nadia M. El-Shafey^1,*,Raifa A. Hassaneen², Mahmoud M. A. Gabr³ and Osama El-Sheihy⁴
1Botany Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62511, Egypt²Botany Department, Faculty of Science, Ain- Shams University, Cairo, Egypt
³Botany Department, Faculty of Science, Cairo University, Giza, Egypt
⁴Physiology Department, Faculty of Agriculture, Cairo University, Giza, Egypt

*Corresponding author: nadia69shafey@yahoo.com

Abstract

The grains of Oryza sativa L. Sakha 101 cultivar (salt tolerant) were irradiated with 0.0, 5, 10 and 15 KR of gamma rays and their mature embryo-derived calli were exposed to different levels of drought-stress, in order to reveal the bases of physiological behavior of in-vitro cultured rice under gamma-irradiation or drought-stress. The effect of pre-treatment with gamma-irradiation on the response of rice to drought was also evaluated. The results showed that treatment with PEG highly significantly reduced the fresh and dry weight of the most investigated rice calli. However, the magnitude of loss was much less in the irradiated calli than the non-irradiated ones. For each increase in PEG-stress level there was a concomitant increase in total soluble sugars content of both the non-irradiated and irradiated samples. However, most of the irradiated calli exhibited higher tendency to accumulate soluble sugars than the non-irradiated ones in response to higher PEG concentrations. Though diminishing the content of most mineral elements by PEG, the irradiated cells could keep more of their phosphorus, K⁺, Ca²⁺ and Mg²⁺ than the non-irradiated ones. Polyamines (PAs) accumulated in rice calli under drought or radiation-stress. Accumulation of Put and Spd was higher than Spm in response to radiation-stress, while that of Spd and Spm was higher than Put in response to drought. While drought stress caused the disappearance of the 78 and 45 kDa polypeptides, radiation increased their expression. The 93 and 30 kDa polypeptides were expressed only under drought stress either with or without irradiation. The 69 and 60 kDa polypeptides were intensified in response to both radiation and PEG. It was concluded that the pre-exposure to gamma-irradiation had alleviated the harmful effect of drought on rice calli.

(Pages 268-277) PDF Text

Effect of conventional, SRI and modified water management on growth, yield and water productivity of direct-seeded and transplanted rice in central Thailand

G.A. Sanjeewanie Ginigaddara and S.L. Ranamukhaarachchi*

Asian Institute of Technology, P.O Box 04 , Klong Luang, Pathumthani 12120, Thailand

*Corresponding author: ranamuka@gmail.com

Abstract

Innovations in water saving technologies are the foremost needs in today’s rice production as water has become the most limiting resource in agriculture. This study was conducted for evaluating conventional, system of rice intensification (SRI) and modified water management methods in direct-seeded and transplanted rice in order to determine the best water management practice that increases grain yield and water productivity. A 2x3 factorial experiment, where two methods of establishment [viz. direct seeding and transplanting with 8 day old seedlings (TPR)] and three water management methods [viz. conventional water management (CWM), two-week irrigation followed by two-week non-irrigation (2W-2N) and one-week irrigation followed by three week non-irrigation (1W-3N)], was conducted in a randomized complete block design with four replicates. Soil moisture contents at 0-15 cm and 15-30 cm soil layers reached near the lower levels of the readily available water (RAW) during non-irrigation periods in 2W-2N and 1W-3N, but never depleted below RAW level. There were interactions between establishment method and water management for leaf area index (LAI), root parameters, yield and yield components, harvest index and water productivity. Conventional water management was inferior to 2W-2N and 1W-3N, and direct seeding and transplanting had no difference. Overall results showed that there are greater benefits of water saving, yield and net income with 1W-3N water management combined with direct seeding over SRI and CWM and transplanting for 120-day old Suphan Buri 1 hybrid.

(Pages 278-286) PDF Text

Regeneration and genetic transformation of Tossa Jute (Corchorus olitorius L.)

Mohammad Saiful Islam^{1, 2}, Kazi Md. Kamrul Huda², Firoz Mahmud², Sufara Akhter Banu², and Myeong-Hyeon Wang*

^1*School of Biotechnology, Kangwon National University, Chuncheon, Kangwon-do, 200-701, South Korea
²Dept. of Genetics and Plant Breeding, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh

*Corresponding author: mhwang@kangwon.ac.kr

Abstract

The experiment was conducted to establish an efficient and reproducible protocol for the plant regeneration and genetic transformation, which can be used for the improvement of tossa Jute (Corchorus olitorius L.). It was demonstrated that the percent of seeds germination in agar based medium found to be very low (43.1%) , as compared to clinical cotton supported MS liquid medium, which was found to be very high (97.6%) and the highest percentage of root initiation was recorded for the variety O-9897 (53.6%) which was statistically identical by variety O-72 (49.4%) .The performance of varieties in A. tumefaciens showed significant difference in respect of number of explants produced shoot and percent shoot regeneration. Variety O-9897 gave the best performance as compared to variety O-72. In transformed explants, GUS reporter gene was expressed showing blue color in the explant tissues. Non-transformed explants did not show any color. Variety O-9897 showed the highest response to GUS assay (86.6%) as compared to O-72 (80.0%). This efficent regeneration and transformation system can be further used for the improvement of Jute quality using other useful genes.

(Pages 287-293) PDF Text

The effect of glycinebetaine or ascorbic acid on grain germination and leaf structure of sorghum plants grown under salinity stress

Arafa A. A, Khafagy M. A. and El-Banna M. F.

Agriculture Botany Department, Faculty of Agriculture, Mansoura University, Mansoura, Egypt

Abstract

The effects of exogenously applied glycinebetaine or ascorbic acid (pre-soaking or pre-soaking plus spraying) on sorghum seedlings grown under salt stress were investigated. The seedlings were grown in hydroponic culture containing nutrient solution for 3 weeks and treated with NaCl at 1500, 3000 and 6000 ppm. Salinity increased significantly the germination percentage of sorghum grains when applied at low level but tended to decrease as the concentration of salt was raised. Ascorbic acid or glycinebetaine either alone or in combination with salinity increased germination percentage and ascorbic acid was more effective in this respect. Concerning leaf anatomy it was found that low salinity level (1500 ppm NaCl) increased the blade thickness, xylem and phloem tissues thickness and metaxylem vessel diameter as well as main vascular bundle dimensions. At the same time, moderate and high salinity levels (3000 and 6000 ppm NaCl) decreased all these parameters. The great reduction was observed under high salinity level. However, ascorbic acid or glycinebetaine had a stimulating effect in this respect and glycinebetaine proved to be more effective in this respect particularly in case of pre-soaking plus spraying method. On the other hand, salinity induced leaf cell damages in leaf sorghum plant as compared to control plants. It could be concluded that glycinebetaine or ascorbic acid applications could minimize the harmful effects of salt and pre-soaking plus spraying was found to be more effective than that of pre-soaking application.

Key words: Sorghum, salt stress, nutrient solutions, antioxidants, osmoregulators, leaf anatomy

(Pages 294-304) PDF Text