Phenotypic evaluation and molecular profiling of Brassica juncea (L.) lines carrying introgressions from Erucastrum abyssinicum
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Date
2014
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Punjab Agricultural University, Ludhiana
Abstract
Introgression lines (ILs), created in Brassica juncea, following hybridization with Erucastrum abyssinicum were studied to catalogue their genetic diversity and crop performance under stressed ecologies. Molecular data generated following amplification with 72 SSR markers (35 (A genome) and 37 (B genome)) suggested the occurrence of high genetic diversity. ILs like JA-85, JA-128, JA-77, JA-30, JA-72, JA-96, JA-196, JA-95, JA-75 fell in Cluster 1 along with E. abyssinicum and were amongst those lines that carried a very large chunk of genomic information from the wild donor species. Graphical genotyping revealed that percent introgression varied from 12.5% to 40% with maximum introgression in JA-30, followed by other ILs like JA-85 (39.9%), JA- 53 (38.3%), JA-128 (37.4%), JA-75 (37.4%), JA-77 (36%), JA-96 (35.9%), JA-95 (35.1%), JA-72 (34.9%), JA-196 (34.1%), JA-245 (33.7%). Least introgression from the donor parent was recorded in JA-24 (12.5%). On the whole, maximum introgression was seen in chromosome 3 of ‘B’ genome which had 43.2 percent introgression from the donor parent. Morphological evaluation helped to identify useful ILs for earliness and components associated with crop productivity. Some of the ILs like JA-344 (number of primary branches), JA-92 (number of siliqua on main shoot), JA- 42 (siliqua length), JA-159 and JA-235 (seeds per pod), JA-192 (seed yield) performed equally well in both the environments. Grain yield was positively associated with flowering, plant height, leaf area index etc. which indicated that higher yield can be achieved by bringing changes in these parameters. GG Biplot analysis also confirmed a high level of variation for all the traits studied. Morphological data for test characters was also used to generate Euclidean distance graphs based on Mahalanobis D2 analysis and the ILs were clustered in 10 groups. The growing unpredictability of climate requires breeding of cultivars adapted to broad environments. Three ILs namely JA-59, JA-65, JA-240 were able to tolerate high temperature while 16 ILs viz. JA-22, JA-31, JA-35, JA-38, JA-45, JA-65, JA-127, JA-147, JA-149, JA-174, JA-193, JA-233, JA-331, JA-343, JA-352 and JA-36 could tolerate low temperature stress during flowering. These ILs can further be used in future breeding programmes suited for the development of varieties for stressed ecologies.