Studies on inheritance of major quantitative and qualitative traits in soybean {Glycine max (L.) Merrill}
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Date
2009-10
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was carried out to know the nature and magnitude of gene effects governing the seed yield and its components along with correlation, heritability, genetic advance and certain qualitative traits at the G.B. Pant University of Agriculture and Technology, Pantnagar(India) during Kharif 2008-09. Four parental soybean genotypes three of which were released varieties viz., UPSM 534, PS 1347, JS 335, along with a wild spp. G. soja, were used to develop three crosses viz., PS 1347 x G. soja, PS 1347 x JS 335 and JS 335 x UPSM 534. Five generations namely, P1, P2, F1, F2 and F3 of each of these three crosses in a Compact Family Block Design with three replications were evaluated for the study of various genetic parameters. Observations on nine major quantitative characters viz., days to 50 % flowering, days to full maturity, plant height, number of pods per plant, seed yield per plant, dry matter weight per plant, harvest index, oil and protein content. Five qualitative traits viz. growth habit, leaf shape, flower color, pubescence color and yellow mosaic virus incidence were also studied for finding goodness of fit to the Mendelian segregation ratio. Highly significant/significant mean squares values for most of the characters suggested inherent genotypic differences in the experimental material for different quantitative traits. The broad sense heritability estimates were higher for dry matter weight per plant. However, number of pods per plant, dry matter weight per plant and plant height revealed high genetic advance. Thus breeding program should be planned to increase seed yield having low heritability and have good associations between certain agronomical characters and seed yield. Knowledge of relationship among yield and the other agronomic traits is of great importance in plant breeding, especially for the selection of genotypes for higher seed yield. Correlation studies showed that seed yield had significant positive correlation with plant height, number of pods per plant, dry matter weight and harvest index. The estimates of scaling test and five genetic parameters revealed predominance of both additive as well as non additive gene action for most of the characters. Both types of epistasis were also found in the present study. Presence of duplicate type of epitasis in almost all the crosses for various quantitative characters indicated complex nature of inheritance. Therefore, in this situation simple selection is likely to be useful for effective utilization of both types of additive and nonadditive gene effects simultaneously. The inheritance of qualitative traits revealed that growth habit, leaf shape, flower color, pubescence color segregated in 3:1 ratio and governed by monogenic inheritance whereas, inheritance of yellow mosaic virus resistance was found to follow 15:1 pattern and governed by two recessive genes in JS 335 x UPSM 534 cross. Based on the observations derived from the present investigation, it is therefore suggested that more emphasis should be given for the improvement of yield components viz., dry matter weight per plant, number of pod per plant, harvest index in soybean crop.
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Thesis-PhD
Keywords
inheritance, quantitative traits, qualitative analysis, soyabeans, Glycine max, yield components, dry matter, harvest index