Studies on some morphological characters and yield attributes of synthetic Brassica hexaploids and their parents

Allopolyploidy plays an important role in plant evolution and confers better advantages on crop growth and breeding compared to low ploidy levels. The present investigation aimed to study the synthetic hexaploid Brassica (AABBCC genome) developed from Brassica cainata (BBCC genome) and Brassica rapa (AA genome) compared to their parental genotypes considering some morphological characters, yield attributes and yield. Increased vegetative growth in hexaploids over their parents was observed. Hexaploids exhibited wider ranges with higher coefficients of variations compared to the parents for all characters studied. Hexaploids had taller plants, higher number of siliqua and larger flowers than those of both parents. Though average pollen fertility in the hexaploids was lower than both parents but out of 420 hexaploids, seventeen had comparatively higher percentages of pollen fertility as well as siliqua setting. Number of seeds per siliqua and siliqua length were found to be lower than their parents. Mean seed weight per plant in the hexaploids was lower than the parents though the hexaploids had higher number of siliquae along with higher seed weight. Days to flowering and maturity in the hexaploids were in between the parents and closer to the B. carinata parent. Five hexaploid plants from BARIBatishak-1 × Carinata-1 and two from each of Carinata-1 × BARIBatishak-1 and Agrani × Carinata-1 were found to be promising because they have higher seed yield per plant than their parents. Those nine selected high yielding hexaploid plants could be evaluated in the subsequent generations to select the stable and desirable Brassica hexaploids.Keywords: Brassica hexaploid, morphological characters, yield attribute