australian journal of crop science   AJCS

Field application of plant resistance inducers (PRIs) to control important root rot diseases and improvement growth and yield of green bean (Phaseolus vulgaris L.)

Riad Sedki Riad El-Mohamedy, Mohamed Reda Shafeek, Emad El-Din Hassanein Abd El-Samad*, Dina Mohamed Salama, Fatma Ahmed Rizk

Plant Pathology Department, National Research Centre, 33 El-Buhouth St., Dokki, Giza, Egypt, Postal Code: 12622.
Vegetable Research Department, National Research Centre, 33 El-Buhouth St., Dokki, Giza, Egypt, Postal Code: 12622.

Abstract

The efficiency of plant resistance inducers (PRIs) i.e. chitosan (CH), salicylic acid (SA) and humic acid (HA) in controlling Fusarium solani and Rhizoctonia solani the causal agents of root rot diseases under in vitro and on growth and yield of green bean cv. Giza 3 were evaluated. In vitro treatments of CH 1.0 g/l, CH 1.0 g/l + HA 5.0% and CH 0.5 g/l + SA 2.5%, as sterilized PDA medium addition, caused the highest reduction in mycelia growth and spore germination of F. solani and R. solani on incubated plates compared to control plates (medium free of inducers). Under greenhouse conditions, combined treatments of PRIs were superior than single treatments, while, CH 1.0 g/l + SA 5% or HA 5.0% treatments were more effective than single treatments in controlling of Rhizoctonia root rot. These treatments caused disease reduction reached to 70.4 and 67.4% of pre-emergence stage after 10 days of seed sowing, and 62.8 and 60.4% of post-emergence stage after 40 days of seed sowing. Meanwhile, the highest values of survival plants 79.4 and 77.8% were recorded with the same treatments. Under field conditions, the obtained results indicated that soaking bean seeds in CH 1.0 g/l + SA 5% followed by foliar application with half of this concentrations CH 0.5 g/l + SA 2.5%, (for 3 times in 7 days interval starting from the second true leaf stage), resulted in the higher percentages of reduction of damping-off and root rot incidence 68.2, 63.8, 70.0% and 67.4, 63.3, 69.6% after 10, 40 and 60 days during both seasons, respectively, compared with other treatments. Furthermore, such treatment was superior than commercial fungicide seed treatment in controlling of green bean root rot, where, fungicide treatment reduced damping-off and root rot incidence after 10, 40 and 60 days up to 64.6, 60.4, 64.0% and 64.0, 59.6, 63.4% during both seasons. Combined treatments of PRIs and commercial fungicide treatment resulted in increasing of vegetative growth characters, yield and quality of green bean pods compared to other treatments during two successive seasons. It could be suggested that using plant resistance inducers in comparison with fungicides, might be considered as an eco-friendly, safe, cheap and easily applied method for controlling such soil-borne plant pathogens considering the avoidance of environmental pollution and the side effects of fungicides application.

Pages 496-505 | Read More| doi: 10.21475/ajcs.17.11.05.p260
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Evaluation of genotype x environment interaction using GGE-biplot on dry beans (Phaseolus vulgaris L.) in Limpopo province of South Africa

Rudzani Mathobo*, Diana Marais

Department of Plant and Soil Sciences, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
Limpopo Department of Agriculture, Private Bag X9487, Polokwane, 0700, South Africa

Abstract

Dry bean is the second most important legume crop in South Africa due to its high protein content. GGE- Biplot was used to evaluate genotype x environment interaction (GEI) and stability performance of dry bean genotypes during 2011 and 2012 growing seasons. Eight dry bean genotypes were planted at different locations in the Limpopo province, South Africa with different agro-climatic characteristics. The genotypes used were OPS-RS1, Jenny, Kranskop, DBS310, OPS-RS4, DBS 360, OPS-RS2 and OPS-RS5. The ANOVA analysis results for grain yield, number of pods per plant and number of seeds per plant revealed that the environment contributed more to the total variation followed by GEI and finally genotype. According to GGE biplot for grain yield, OPS- RS1 was regarded as the more stable genotype and had the highest mean yield, DBS 360 had the highest mean number of pods per plant and DBS 310 produced the highest mean number of seeds per plant. The GGE biplot methodology clearly presented the GEI relationship among environments and genotypes.

Pages 506-515 | Read More| doi: 10.21475/ajcs.17.11.05.p303

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Correlation among adaptability and stability assessment models in maize cultivars

Tâmara Rebecca Albuquerque de Oliveira*, Hélio Wilson Lemos de Carvalho, Emiliano Fernandes Nassau Costa, José Luiz Sandes de Carvalho Filho

Center for Agro-Food Science and Technology, State University of Northern Fluminense, Rio de Janeiro, RJ, 28035-200, Brazil

Embrapa Tabuleiros Costeiros, Aracaju, SE, 49025-040, Brazil

Federal Rural University of Pernambuco, Recife, PE, 52171-900, Brazil

Abstract

The aim of the current study is to associate four different adaptability and stability analysis models using the Spearman’s correlation based on productivity data. Twenty-five (25) hybrid maize cultivars were assessed in 11 environments located in the Brazilian Northeastern region, between 2012 and 2013. The study has followed a complete randomized block design with two repetitions. There was high correlation between the methods by Cruz et al. and Eberhart and Russel. Both methods have shown mean correlation with the method by Verma et al. With respect to favorable environments, the methodology by Lin and Binns has shown high correlation with the methods by de Cruz et al. and Eberhart and Russel, as well as negative correlation with the method by Verma et al. The methods by Lin and Binns and Verma et al. should not be used together, since there was no correlation between them. The combined use of the methods by de Cruz et al. and Eberhart and Russel has provided the best genotype selection results, since these methods associated productivity data with the cultivars’ stability and adaptability. Therefore, these methods were the most adequate for this type of analysis.

Pages 516-521 | Read More| doi: 10.21475/ajcs.17.11.05.p304

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Effect of spacing on mini watermelon hybrids grown in a protected environment

Abstract

In recent years, a group of small watermelons has stood out with 1–3 kg in weight called mini watermelons. These watermelons, when grown under greenhouse conditions, require different management techniques. This study evaluated the performance of mini watermelon hybrids at different plant spacing. To this end, the experiments were conducted in a greenhouse using a substrate of coconut husk fibers with fertigation. The study design was a randomized block with 5 × 3 factorial treatments and four replicates. The factors evaluated included five mini watermelon hybrids (Beni Kodama, Ki Kodama, Smile, New Kodama, and Beni Makura) and three plant spacing configurations (E1 = 0.35 m, E2 = 0.50 m, and E3 = 0.65 m). Growth characteristics, production, and quality were evaluated using analysis of variance. There was no significant interaction between the hybrids and plant spacing for yield traits, physiological traits, and fruit quality. Fresh fruit mass, yield, transverse and longitudinal diameter and firmness presented significant differences for both factors, type of hybrid and plant spacing. In this study, despite the established competition in terms of spacing, the performance of hybrids was not negatively affected. Thus, we recommend the cultivation of hybrids spaced 0.50 m apart in coconut husk fibers, because it results in good yield and fruit quality, while facilitating plant management techniques.

Abstract

Anacardium othonianum Rizz., popularly known as the Cerrado cashew tree, is widely used in medicine due to its therapeutic properties, including its antioxidant, anti-inflammatory, and antidiarrheal activities. Light is an important regulator of the growth, development of plants differentiation, and metabolism. Considering the influence of light on the production of phytochemicals, the aim of the present study was to evaluate production of gallic and 3,4-dihydroxybenzoic acids and amentoflavone in A. othonianum seedlings grown in vitro exposure to white, blue, green, red, and yellow light. The seedlings were evaluated with respect to the length of the aerial parts and the number of leaves, at 0, 20, and 40 days of treatment. The fresh and dry weights of the aerial parts and the levels of phenolic acid and biflavonoid were evaluated at 40 days via high-performance liquid chromatography with a diode array detector (HPLC-DAD). Regardless of the light wavelength used for the growth, the largest length of the aerial parts (5.54 cm) and an increase in the number of leaves (2.86-fold) were observed at 40 days. The largest accumulations of fresh weight (325.5 mg and 335.1 mg per seedling) and dry weight (83.3 mg and 84.5 mg per seedling) were observed in seedlings grown under red and yellow light, respectively. Relatively higher levels of gallic acid (0.66 mg.g-1dry weight) and amentoflavone (1.41 mg.g-1dry weight) were found in seedlings grown under blue light. In contrast, the 3,4-dihydroxybenzoic acid levels of the seedlings under red light increased (8.22 mg.g-1 dry weight).

The progress of rice breeding program for better adaptation and extension on inland swamp ecosystem largely depends on the presence of genetic variability and relevant selection criteria. This study was undertaken to estimate the genetic variability parameters in segregating populations of rice and to determine the relationship of grain yield and yield contributing traits of rice to determine selection criteria for yield improvement under inland swamp condition. The F2 population was generated from 11 crosses involving Bengkulu landraces of swamp rice. Then, the F2 population was evaluated on the inland swamp for their yield and yield-related traits. The genetic parameter was estimated using variance component analysis. Simple correlation analysis was performed for all observed traits and the resulting matrix of correlation coefficients was subjected to factor analysis and path analysis. Analysis of variance indicated that significant variation present among and within F2 families for most of the traits studied. Grain yield plant-1 exhibited the highest GCV (40.3 %) and PCV (60.11%). Moderate to high or moderate h2B with high GAM was obtained on plant height, tiller number, number of productive tiller, spikelet number panicle-1, 100-grain weight, and grain yield plant-1. Positive and significant correlation was found between grain yield plant-1 and plant height, tiller number, spikelet number panicle-1, panicle length, and 100-grain weight. Factor analysis discerned the 9 observed traits into two-factor axes with overall explaining 79.28% of the total variation among traits. The first factor (59.12%) was strongly characterized by yield and yield components (plant height, tiller number, number of productive tillers, spikelet number panicle-1, panicle length, and 100-grain weight), whereas the second factor (20.16%) was mainly associated with heading date. Path analysis revealed that among the yield components, tiller number and 100-grain weight (the grain size) had strong direct effects on grain yield and they can be taken into account as the selection criteria for rice grain yield improvement under inland swamp ecosystem.

Sulphur (S) topdressing and organic compost in production, quality and nutrients accumulation of broccoli seeds at planting time

Carla Verônica Corrêa*, Aline Mendes de Sousa Gouveia, Natália de Brito Lima Lanna, Bruno Novaes Menezes Martins, Ana Emília Barbosa Tavares, Veridiana Zocoler Mendonça, Antonio Ismael Inácio Cardoso, Regina Marta Evangelista

Department of Horticulture, Botucatu School of Agronomy (FCA), Universidade Estadual Paulista (UNESP), Botucatu, São Paulo state, Brasil

Abstract

Most recent studies have focused to the nutrition and fertilizer recommendations of commercial broccoli production. There are a few studies on effect of fertilization on seed production. Although Brazil is a major producer of vegetables, research on seed production of broccoli is scarce. Therefore, it is necessary to develop research lines that increase the information regarding the nutritional requirements for seed production, since in broccoli; there is a 60 days cycle for production, which leads to the understanding of a greater nutritional need of the crop. It is known that sulphur is the second most accumulated nutrient in broccoli seeds. This study aimed to evaluate the effect of doses of sulphur topdressing; and organic compost fertilization on the production and quality of broccoli seeds at planting. The experimental design was a randomized complete block, with ten treatments (5x2 factorial design) and four repetitions. Treatments consisted of five doses of S topdressing (0, 58, 115, 173 and 230 kg S.ha-1) in the presence or absence of organic compost (100 t ha-1) at planting stage. Seed production (mass and number per plant), mass of thousands of seeds, seed quality (germination, first germination count, germination speed index, seedling length, and seedlings fresh weight); and macronutrients accumulation in the seeds were evaluated. The amount of seeds per plant was 9836 and 8005 seeds per plant in the presence or absence of organic compost, respectively. The seeds fresh mass of 45.7 and 33.1 g of seeds per plant was produced with and without organic compost, respectively. However, the other characteristics, such as total germination (G), first count (FC), germination index rate (GIR), and seedling fresh mass (SFM) did not reach any significant differences. Regarding to the doses of sulphur, a linear increase was detected to the equation for all macronutrients extracted in the absence of organic compost at planting. However, in the presence of organic compost (100 t ha-1) at planting, a linear equation was obtained for P, Mg and S. For the other macronutrients, a quadratic function occurred, with average values of 2329.2, 431.4 and 326, 5 mg plant-1 at the maximum doses estimated in 165.56, 146.50 and 171.42 for N, K and Ca, respectively.

Abstract

Mutants are powerful genetic resources in plant breeding and functional genomics studies. Sixty seven stable ethyl methane sulphonate (EMS) induced rice mutants and the wild type parent Nagina 22 (N22) were characterized for plant height, tiller number, panicle number and grain yield under normal, low P field and alternate wet and dry (AWD) conditions in the same season. They were also genotyped with 44 SSR markers and four Pup1 (Phosphorus uptake1) gene specific markers. Genetic diversity was analysed by combining phenotype and marker data using Ward- MLM method. Single marker analysis showed significant association of four markers RM19696, RM263, RM3688 and RM1942 with grain yield in all three conditions. K-1, a Pup1 gene specific marker was significantly associated with tiller number only under low P conditions. The average dissimilarity between mutants was 0.86 and cophenetic correlation coefficient was 0.74. Six mutants were selected as gain-of-function mutants as they showed significantly higher grain yield in all three conditions, compared with N22. The selected mutants are an important resource for gene discovery for enhanced tolerance to low P and water stress conditions and associated markers can be useful in marker assisted selection.

Sorghum is among the most important cereal crops produced globally due to drought tolerance nature and multiple uses. Ethiopia is endowed with high genetic diversity for sorghum and the main sources of several genes that are responsible for biotic and abiotic stress tolerance. Despite these potentials, sorghum productivity in the country remains very low. The study was designed to screen and compile the best simple sequence repeats (SSRs) that can be used for marker-assisted breeding of sorghum. Out of the total 304 SSRs used across eleven farmers preferred sorghum genotypes, nearly half of the markers 139 (45.7%) detected 543 alleles and a high degree of polymorphism information content (PIC) averaging 0.53.The overall observed heterozygosity (Ho) over loci varied from 0.00 to 1.00 with an average of 0.16. Nearly 60 % (83 markers) showed zero value for Ho. The gene diversity index (expected heterozygosity, He) ranged from 0.17 to 0.91 with a mean of 0.58. The weighted neighbor-joining cluster analysis grouped the genotypes into three distinct groups. All genotypes with stay-green features (B 35, Sorcoll 163/07, E 36-1 and Sorcoll 141/07) were clustered together. Genotypes such as Gambella, Macia, 76T#23 and Meko were clustered in the second group. The third group consists of Teshale and Sorcoll 146/07. Most of the used SSR markers were linked with stay-green traits and successfully discriminated genotypes with stay green (cluster I) from those genotypes with non-stay green features (cluster II and III). The result reveals the potential application of microsatellites in Ethiopian marker-assisted breeding program for further characterization and/or mapping of targeted traits in sorghum.

Abstract

The effect of P on different plants and several growth stages are well known to scientists, but there is little information on the effect of P after transplanting the seedling until harvesting. The current study aimed to evaluate the effect of P on tomato seedling and fruit production of Paronset hybrid. Therefore, six treatments (0, 15, 30, 45, 60 and 75mg L-1P) were evaluated in a randomized complete block design with four replications. Monoammonium phosphate (MAP) was used as P source, in addition to coconut fiber substrate. A linear increase was obtained for leaf area, seedling height, shoot and root fresh matter at 75mg P L-1. However, yield and fruits characteristics were not affected by increasing P doses on seedlings.

The knowledge of the correlation between the spatial variability of soil attributes and crop yield is necessary for defining precision agriculture practices. The objective of the present study was to characterize soybean yield by mapping the spatial variability of the soil texture and apparent electrical conductivity for the delineation of management zones. The study was conducted in a field located in the Brazilian Savannah. The soybean yield, soil texture, and apparent electrical conductivity of an Oxisol were analyzed and mapped. The management zones were generated using the data from the spatial dependence of the mapped variables. The soil map that correlated best with the yield map was determined. The management zones were defined using the apparent soil electrical conductivity with the highest Kappa coefficient (0.30) for the soybean yield. The results demonstrate the potential utility of apparent soil electrical conductivity map for agriculture precision.

Soil water content is one of the most significant restriction factors for plant growth and development. This study focused on evaluating the methods of soil moisture maintenance during trials under controlled conditions by observing the morphological and structural characteristics of sunflower (Helianthus annuus L.). The experiments were performed in a greenhouse using an Oxisol. Four types of soil moisture maintenance treatments were tested (tensiometer, Irrigas, gravimetric method and self-irrigation system) with eight repetitions, employing a completely randomized experimental design. The variables analyzed included plant height, leaf number, stem diameter, and dry mass of shoot. The self-irrigation system was found to be technically fitting to manage the irrigation throughout the growth and development period of sunflower. The gravimetric method enabled a higher accumulation of dry mass of shoot.

Abstract

Yield, yield components, antioxidant activity and genetic variation of fifty genotypes on Vigna spp. were evaluated under two production systems (inorganic and organic agricultural systems) at the field trails in the Kingdom of Thailand. The experimental design was a Randomized Complete Block Design with four replications and twenty plants in blocks. It was found that pod length, fresh pod weight, number of seeds, number of pods, fresh pod yield, 100 seed weight and harvest index showed significant difference (p≤0.05). The highest quality number of pods was found on Fakdang 71.75 and 55.25 pod.plant-1 under inorganic and organic agricultural system, respectively. The Kangkragan produced the highest quality yield 1,385.20 and 1,135.30 g.plant-1 under inorganic agricultural system and organic agricultural system, respectively. Suarpran had the lowest quality yield 208.10 g.plant-1 under organic agricultural system. The highest values for trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability (DPPH) were obtained from Panomsarakram and Fakdang (95.36 and 35.61% of inhibition, respectively). The outcome of this study can be used as guidance for Vigna spp. production in Thailand.

Abstract

The present study investigated the removal of cadmium from low quality water by bentonite applied in the soil using with the plants test radish, corn and sugar beet. The experiments were carried out in a greenhouse, with a completely randomized design with four replications. The experimental units were plastic pots with a capacity of 5 kg for beets and radish; and for corn in plastic pots with 14 kg. The soil was mixed with increasing doses of bentonite equivalent to 0; 30; 60 and 90 t ha-1. The sowing was done directly on the pot, leaving two plants per pot after thinning. They have been irrigated with poor quality water with a concentration of 0.2 mg L-1 Cd. Plants of radish, corn and beet were harvested at 30, 60 and 90 days, respectively, separated in shoot and roots and placed in air circulation oven. The data were submitted to analysis of variance. The present study led to demonstrate that application of bentonite in soil irrigated with poor quality water had a significant positive effect on development of radish, corn and beet crops, ie, influenced at 1% probability the dry biomass of roots of radish, corn and beet and the dry biomass of shoot of the corn. Generally the bentonite promoted the retention of cadmium in the soil, evidenced by the reduction of the concentration and/or accumulation of this metal in the shoot and roots of radish, corn and beet. Bentonite favored the reduction of bioaccumulation and translocation factors of cadmium thereby increasing the concentration of this element in soil in relation to the plants and in shoot in relation to root, except of corn.

Density of soil and nitrogen in production and nutrition of safflower (Carthamus tinctorius L.)

Abstract

The objective of this study was to evaluate the production and nutrition of safflower under different densities of soil and nitrogen rates in Oxisol. The experiment followed a randomized complete block design and was performed in a greenhouse in a factorial 5x5 fractionated scheme (5²), involving five soil densities (1.0, 1.2, 1.4, 1.6, and 1.8 Mg m-3) and five nitrogen rates (0, 50, 100, 150, and 200 mg dm-3), with four replications. The variables analyzed included the chlorophyll index, dry mass of the shoot, dry mass of the head, and concentration of nitrogen accumulation in the shoots and heads. The dry mass and nitrogen accumulation in the shoot and heads of the safflower showed a 50–53% drop as the soil density increased. Nitrogen rate of 149 and 179 mg dm-3 produced a higher chlorophyll index and nitrogen concentration in the safflower plant heads, respectively. The concentration and shoot nitrogen accumulation revealed a 49% and 37% rise, respectively, with increased nitrogen fertilization. As the soil density and nitrogen levels influence the production and nutrition of safflower, they were isolated.

Abstract

Research results on agronomic techniques for chia are still few, although this culture is very widespread. The study was carried out under greenhouse conditions, from June to August 2016, in the city of Campina Grande, PB, Brazil, with geographic coordinates 7º13’11’’ S, 35º53’31’’ W and altitude of 547.56 m. During this period the average air temperatures inside the greenhouse varied between 23.7 °C and 33.8 °C, with mean relative humidity around 52%. The objective of this study was to investigate the effects of nitrogen, phosphorus and potassium fertilization application on the development of chia. The research consisted of three independent experiments, following a completely randomized design to evaluate the performance of nitrogen (N), phosphorus (P) and potassium (K) in six doses, with three replications. Each experimental unit consisted of a plastic vase filled with 8 kg of sandy soil. The nutrient doses were as follows: 0; 25; 50; 75; 100 and 125 kg ha-1 of N; 0; 20; 40; 60; 80 and 100 kg ha-1 of P and 0; 20; 40; 60; 80 and 100 kg ha-1 of K. Analysis was made of the height of the plants (30 and 60 DAS) (measured with a graduated ruler), number of leaves and of inflorescence per plant and weight of the dry biomass. First results indicate that the nitrogen, phosphorus and potassium doses favored the growth of chia plants in relation to control promoting an increase in all studied variables, evidencing the necessity of cultivation by these elements. In general, considering the values of the variables according to the increasing doses of nutrients, a preliminary recommendation could be indicated, under the conditions of this research, as 125: 100: 40 kg ha-1 of N: P: K. So the effect of these nutrients on chia need to be more investigated.

Nitrogen fertilizer effect in production, nutrient accumulation and nitrogen efficiency use of second ratoon sugarcane harvested without straw burning

Abstract

Sugarcane harvest after straw burning implies rapid mineralization of biomass and greenhouse gas emissions. In this context, maintenance of sugarcane straw on the soil is as a new strategy to circumvent the harmful environmental effects, but imposes a new dynamic regarding nitrogen in the soil-plant system. This study sought to evaluate the effect of nitrogen fertilization on biomass production and nutrient accumulation in leaf (senescent and young) and stalks of sugarcane plant from the second sugarcane ratoon, variety SP 83-2847, harvested mechanically in 2007 after six years without straw burning for six years. This study adopted a randomized block design with five nitrogen doses application (0, 60, 120, 180 and 240 kg ha-1) in the form of ammonium nitrate and four replications. Nitrogen fertilization promoted an increase in leaf (senescent and young) and stalk production of the sugarcane plants. However, excess nitrogen decreased accumulation of macro and micronutrients and nitrogen use efficiency by sugarcane due to dilution effect. Although straw deposition on the soil surface of the sugarcane field had occurred for six years, but mineralization of organic matter from the straw did not provide sufficient nitrogen for the growth of sugarcane plants in control treatments, requiring nitrogen application via fertilization. There is a need to adopt new nitrogen fertilization strategies in order to increase nitrogen use efficiency for greater production of sugarcane.

Effect of chitosan on physiology, photosynthesis and biomass of rice (Oryza sativa L.) under elevated ozone

Abstract

This research aimed to study the effects of chitosan on physiology, photosynthesis and biomass of rice cultivar RD47 under elevated ozone. Rice samples were grown at indoor climate controlled chambers, allowing the inlet air to pass through charcoal filters. For combined effects of chitosan and ozone, rice was soaked and sprayed with chitosan 0.05% (W/V) under elevated ozone concentration at 40 ppb (Chi+EO340) and 70 ppb (Chi+EO370). Control groups (CF) with no additional ozone were also studied. Samples were analyzed weekly for tiller number per plants, leaf area, leaf chlorophyll, photosynthesis, shoot biomass, root biomass and total biomass. The results obviously showed that ozone at the concentration of both 40 and 70 ppb caused negative effects on rice physiology, photosynthesis and biomass. The 70 ppb concentration, particularly, caused sever damage. Whilst soaking and spraying with chitosan could significantly reduce the harmful effects of ozone compared with the control group. For the samples soaked and sprayed with chitosan under elevated ozone for 21 days, Chi+EO340 and Chi+EO370 significantly performed more photosynthesis and contained more leaf chlorophyll than EO340 and EO370, respectively (p ≤ 0.05). In addition, chitosan could reduce the ozone negative effects and increased higher physiology and photosynthesis rate. However, there was no significant difference in biomass compared with the control group. Even through, ozone has been gradually increasing which made plants at risk, chitosan treatment could significantly ameliorate the effect of ozone and serve as a plant growth promoter with no harmful to human being.

Abstract

2-acetyl-1-pyrroline (2AP) is the characteristic compound for the fragrant rice. 2AP accumulation in rice can be affected by environmental factors such as salinity, drought stress and solar intensity. In this study, the accumulation of 2AP content during growth of Thai black glutinous rice (Upland rice) was investigated. Furthermore, we also investigated the effect of gamma irradiation on plant growth, grain weight and 2AP content of irradiated rice, compared to non-irradiated rice. The results revealed that 2AP was accumulated in shoots and roots of rice. The highest 2AP content in roots was found in seedling stage I and about 2-fold higher when compared with 2AP in shoots at the same stage. After seedling stage I, the 2AP content of roots decreased and was lower than 2AP content of shoots. The results indicated that 2AP content may be migrated from roots in seedling stage I into other part of rice after this stage. When rice grains were subjected to 137Cs gamma irradiation, shoot length, 2AP content and grain weight of irradiated rice was investigated and compared with non-irradiated rice. Shoot length of irradiated rice was higher than non-irradiated rice at low gamma dose, while the high gamma dose inhibited the shoot length of irradiated rice. The trend of 2AP content in shoots and roots of irradiated rice in some gamma doses were higher than non-irradiated rice. Moreover, the 2AP content of shorter irradiated rice shoots seems to be higher than of longer-irradiated rice shoots. The gamma ray caused the reduction of grain weight in irradiated rice, while the 2AP content in grain of irradiated rice was higher than non-irradiated rice. This report suggests that the gamma irradiation technique cloud induce the growth of rice and improve the 2AP content in rice.