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Subject: Plant Breeding × End date: 2020 × Start date: 2020 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Genetic variability of root traits of different classes of rice (Oryza sativa L.) in Assam
    (AAU, Jorhat, 2020-10) Bairagi, Priyanka; Sharma, K. K.
    Root characters for plant selection have been major breeding objectives for development of stress tolerant varieties in rice. Therefore the present investigation was conducted for comparative study of root traits and some yield attributing traits in different classes of rice (Ahu, Sali, Bao and Hybrid) in Assam. The study revealed presence of genetic variability among the genotypes for all the root and yield attributing traits. Bao varieties showed maximum root development throughout its growth period upto maturity in comparison to the other classes of rice. Highest phenotypic coefficient of variation and genotypic coefficient of variation was observed for the root length, root volume and root: shoot ratio. Heritability in broad sense was found to be high for root length, plant height, root volume and root: shoot ratio. Genetic advance as percentage of mean was found to be maximum for the root: shoot ratio, root volume and root length. High heritability along with high genetic advance as percentage of mean indicates presence of additive gene action and simple selection procedure can be adopted for improvement of yield. Correlation coefficient revealed positive association of fresh root weight, root: shoot ratio, total tillers per plant, effective tillers per plant with grain yield per plant respectively at genotypic level. Higher genotypic correlation coefficient indicates less influence of environmental effects on traits. Genotypic path analysis revealed 1000-grain weight, fresh shoot weight showed highest positive direct effect on grain yield. D2 analysis revealed total 11 numbers of clusters and cluster I and cluster VII showed highest numbers of genotype (5 each). Contribution of traits to total divergence was observed highest for root length followed by root volume and plant height. Inter cluster average distance was found to be maximum between cluster VIII and XI; IV and VIII and intra cluster average distance was found to be maximum for cluster I followed by cluster VII and cluster II. Clustering pattern of the genotypes revealed it did not follow any particular pattern with respect to the origin of the genotypes. Parental lines selected from cluster IV, VIII and XI can be used for hybridization programme.
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    ThesisItemOpen Access
    ASSESSMENT OF GENETIC VARIABILITY FOR GLUCOSINOLATE IN A SET OF INDIAN MUSTARD (Brassica juncea L. Czern and Coss.) GENOTYPES AND THEIR RELATIONSHIP WITH ECONOMICALLY IMPORTANT AGRONOMIC TRAITS
    (AAU, Jorhat, 2020-09) Lenka, Devidutta; Phukan, Rumjhum
    Brassica juncea (L.) Czern & Coss. known as Indian mustard is one of the most important oilseed crops of the country occupying considerably larger acreage among the Brassica crops. The mustard plants are much taller than that of toria (Brassica rapa). It has a solid stems unlike toria and has a much higher biological yield than toria. However despite these characteristics, mustard is not a favoured crop in Assam because it takes much longer duration to mature and farmers prefer oilseed varieties which are medium to short height and duration. The present study was conducted to study the genetic variability and character interrelationship of 17 quantitative characters along with 2 biochemical parameters between 18 Indian mustard genotypes. The validation of molecular marker linked to glucosinolate QTLs for marker-assisted selection was also carried out. The pooled analysis of variance revealed significant variation among all the genotypes along with 12 characters showed significant genotype x environment interaction. Foot length, seed yield per plant and glucosinolate content exhibited high GCV, PCV, heritability and genetic advance as % mean. From both the years, it was observed that the character seed yield per plant showed significant positive correlation with maximum root length, biological yield per plant and harvest index. Glucosinolate content showed significant and positive correlation with days to 50% flowering, days to maturity and oil content. Days to 50% flowering was highly correlated with the trait oil content. From the path analysis result it was observed that the overall direct effect of characters harvest index and biological yield per plant are significantly higher than positive and negative indirect effect of the other character, thereby exhibiting a high significant correlation of harvest index & biological yield per plant with yield. The banding patterns of 50 SSR markers were studied, out of which 21 primers showed polymorphism. The PIC value ranged from 0.019 to 0.383 with an average of 0.171. Multiple-regression analysis of 17 characters including glucosinolate content was carried out with 18 genotypes. From this analysis, 9 primer pair showed association with 11 characters. Out of these 9 primers which showed association, 6 primers were found to be associated with more than one character. The trait glucosinolate content exhibited association with 3 marker i.e. NI03-H07a, sR7178 and OL10-A03a.