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Genetics and crop improvement aspects of medicinal plants in Ashwagandha should be taken consideration to meet the accelerating pharmaceutical demands. For a better understanding of the genetic basis of root yield and related traits, a 9 × 9 diallel analysis excluding the reciprocals was carried out using SKA 27, SKA 11, SKA 6, SKA 24, SKA 10, SKA 26, JA 20, JA 134 and AWS 1 as parents. The σ2gca/σ2sca denotes that the majority of the traits considered except plant height and the number of secondary branches were governed by non-additive gene action. The fresh root yield was governed by almost equal proportions of additive and non-additive gene actions with a slight increment in additive proportion. Even though none of the parents was a good general combiner for all the traits considered, SKA 27 and SKA 11 appeared to be the best general combiners for root traits. The crosses JA 20 × AWS 1, SKA 24 × SKA 26 and JA 134 ×AWS 1 were found to be appropriate for the heterosis breeding on the basis of the estimates of SCA effects.

A study was conducted during two crop season (Kharif, 2011-12 and 2012-13) for estimating the genetic parameters by involving 10 parents and their 45 F1s in rice crop. The estimates of h2 (overall dominance effects) were positive and significant for days to 50% flowering (9.11), days to maturity (0.24), plant height (2.95), panicle length1(39), productive tillers per plant (3.22), branches per panicle (5.61), flag leaf area (5.50), 1000-grain weight (0.27), biological yield (7.35) and amylose content (1.03) which indicated dominance of genetic components in F1s crosses. The theoretical value (0.25) of (H2/4H¹) for all the traits except kernel length and amylose content indicated the asymmetrical distribution of positive and negative genes in the parents. The proportion of dominant and recessive alleles for panicle length, productive tillers, branches per panicle, 1000 grain weight, biological yield, kernel length and L/B ratio reflected more dominant alleles, whereas for days to 50% flowering, days to maturity, plant height, grains per panicle, flag leaf area, grain yield, harvest index, kernel breadth, kernel length after cooking, elongation ratio, amylose content and hulling %, reflected more recessive alleles in the parents. The estimates of specific combining ability (SCA) effects revealed that the cross Vallabh Basmati 21 x Pusa 1121 could be an excellent candidate for improving grain yield (1.52**), harvest index (1.86**) and flag leaf area (6.20**) whereas Pusa 1121 x CSR 10 is excellent candidate for panicle length (0.89**) and amylose content (1.54**). The characters showing more than 60% narrow sense heritability along with positive and significant correlation with each other and also with grain yield could be rewarding for further improvement of yield and quality in rice. Therefore, these parental lines can be used as donors in future by following bi-parental mating and the diallel selective mating system could be the best breeding method in an early segregating generation for improvement in these traits in rice crop. [ABSTRACT FROM AUTHOR]