GENETIC STRUCTURE OF PAKISTANI OILSEED BRASSICA CULTIVARS REVEALED BY MORPHOMETRIC AND MICROSATELLITE MARKERS

Brassicaceae is a diverse family of economically important crop plants grown worldwide. The rapeseed and mustard are traditional oilseed crops and are being cultivated in Pakistan for centuries. The present study reports genetic divergence among Pakistani oilseeds Brassica cultivars using morphometric and microsatellite markers. Plant material comprised of 31 cultivars of four different Brassica species i.e. Brassica carinata, B. juncea, B. napus and B. rapa including two exotic cultivars. All the cultivars were evaluated under field and laboratory conditions. Significant morphological variation was observed for quantitative traits e.g. days to flowering initiation & completion, days to maturity, leaf size, plant height, 1000-seed weight, leaves per plant, primary branches per plant, main raceme length, silique length and seeds per silique etc. A significant positive association was found between 1000-seed weight, days to flowering initiation and plant height. Seed yield was positively correlated to period of flowering and positively, but non-significant correlation was observed with plant height and number of primary branches per plant. Cultivars, DGL, Pakola, NARC-22, Takwara, Shiralee, Con-III, Dure-NIFA, Abasin-95, Dunkeld, Con-I, Con-II, Chakwal-Sarson and PakCheen-89 were characterized as cultivars having the highest number of siliquae on main raceme with the largest and highly productive siliquae. The PCR-based DNA polymorphism among 30 cultivars revealed significant genetic variation and depicted dissimilarity among cultivars except Dacca-raya and Sultan-raya. Cultivars were classified into 2 major groups and 4 small sub-groups according to their morphological characteristics, origin of cultivars (institute/ research station) and related species. Cultivars like Khanpur-raya, Bahawalpur-raya and Toria-sathi formed no association with other cultivars and positioned independently in the dendrogram.