| Popis: |
In order to enhance commercial production of mustard seed (Brassica juncea) in the tropics, varieties need to be bred that are high yielding, disease resistant and fully adapted to Nigeria’s tropical climate. Four distinct breeding lines of B. juncea obtained from an introduced accession of Indian origin were planted out in a randomized complete block design and characterized for plant height, number of seeds per pod, pod length, leaf length, leaf width, petiole length, 1000-seed weight, and days to first flowering. Five qualitative traits including seed coat color, stem pigmentation, leaf shape, stem pubescence, and susceptibility to lodging were also observed. Analysis of variance revealed significant differences among the breeding lines for the morphological characters studied. High variation was observed for plant height, days to first flowering, leaf length and width, and number of seeds per pod. Pod length, number of branches, seed weight and petiole length exhibited the least variation. Generally, low correlation was observed among different traits but a number of characters were observed to be significantly correlated with one another, indicating some level of association among the traits studied. Principal component analysis resulted in the first two components with Eigen value greater than 1 accounting for 78% of the total variation. Further expansion of the B. juncea gene pool through introduction of exotic genotypes, mutation breeding and hybridization will increase the variation available to breeders for developing desired genotypes that will adapt optimally to the tropical environment. |
