“GENETIC STUDIES AND IMPACT OF WATER STRESS ON YIELD AND QUALITY TRAITS OF RICE”
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Date
2010
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
Of all the abiotic stress that curtails crop productivity, drought is the most divesting one and the most recalcitrant to the breeder‟s effort. Water stress usually has multiple effects on plant growth and development and ultimately affects yield. Water shortage can develop at any time during crop growth; however drought around flowering stage is a recurrent phenomenon in rainfed region. Water shortage during flowering and grain filling stages reduces yield drastically. Two approaches can be followed to improve drought resistance in rice. One approach is to select directly for yield under drought condition or select indirectly using physiological or morphological characteristics associated with drought resistance or combination of both of these strategies. Poor identification of target environments and difficulties in determining meaningful selection criteria contributing to improved yield under stress are reasons commonly advanced for this lack of success. One additional reason is that the field trials to evaluate drought resistance are complex and difficult to manage and very few of them are informative. Conventional breeding approaches have resulted in development of number of improved cultivars, which are suited to low-input rainfed ecosystem; however, many released varieties are not adopted by farmers. The present study was undertaken to study specific adaptability of different rice genotypes and to understand the correlation between different yield and quality traits under different water regimes.
The mean performance of genotypes under three sets of conditions indicates substantial reduction in yield under rainfed and terminal stage drought conditions as compare to the irrigated condition. High heritability was observed for gel consistency, amylose and head rice recovery% under all the conditions and days to 50% flowering and paddy length, number of tillers, grain yield, and number of filled grain for quantitative traits. Biological yield and harvest-index exhibited correlation
with grain yield under rainfed. Number of filled grains per panicle and number of unfilled grains per panicle showed high PCV along with GCV in all three conditions whereas, biological yield and harvest-index showed high performance only in rainfed condition Only character, number of tillers showed correlation with grain yield under irrigated condition. Genotype RF-6/R-1832-RF-17 was found to be the most yield responsive condition under irrigated (E1) condition. Under rainfed (E2) condition genotype ARB-6 yielded highest, the genotype R-RF-44/R-RF-23 showed highest mean for grain yield under terminal stage drought condition. Principal components accounted for 95.20% of total variability in irrigated, 96.23% in rainfed and 98.28% in TSD conditions. Significant variation was observed under agro-morphic characters. Study of flag leaf colour indicating considerable variation in them. Among 42 entries Under irrigated condition 34 entries possessed long bold grains followed by 31 entries under rainfed and 33 entries under TSD condition. While, short bold grains were observed in 8 entries under irrigated, 11 entries under rainfed and 9 entries under terminal stage drought condition observed for all the traits studied and no specific differences were recorded for presence of aerenchyma in the roots of different genotypes, performing differentially under aerobic and anaerobic conditions under root anatomical.
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151 p.