Genotypic variations of phenological and growth parameters in rapeseed (Brassica rapa, var. Toria)

Abstract

Rapeseed is a short duration, self-pollinated and long day crop. It is an important and widely used oil seed crops among the people of Assam and North-East India. However, there is still lack of sufficient rapeseed genotypes for the local farmers. Only a few improved genotypes are recommended in the region. To increase the production and productivity, more numbers of improved genotypes have to be identified. Therefore, a field experiment was conducted at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat, Assam, during rabi 2021-22 and 2022-23 to study the genotypic variations of phenological and growth parameters in rapeseed genotypes. The experiment was laid out in randomized block design with three replications comprising of 22 different genotypes of rapeseed including TS-38 (Check), TS-46, TS-67, TS-36, TS-29, TS-75-1, TS-75-1TL, TS-75-2ME, TS-75-2-MM, TS-76-1, TS-76-2, JT-90-1, Panchali, Bhawani, CG Toria-4, TKM-20-1, TKM-20-2, JT-14-5, PT-2018-09, CG Toria-3, Tapeshwari and PT-303. The crops were grown following the recommended package of practice. All the phenological and growth parameters were taken following the standard methodologies. The result of the experiment indicated significant difference in reaching phenological and growth parameters among the genotypes. The genotype JT-14-5 and TKM-20-2 took the longest duration for 50% flowering and siliqua initiation. However, JT-14-5 and JT-90-1 took the longest duration for physiological maturity. On the other hand, TS-67 and TS-75-1TL took the shortest duration for physiological maturity. The genotype TS-75-2ME showed highest dry weight followed by the genotype TS-38 at harvest. There was gradual increase in Absolute Growth Rate and Crop Growth Rate with the advancement of growth. However, in case of Relative Growth Rate, a decline was noticed in the values from 30-60 DAS to 60 DAS-harvest. The genotype TS-75-2ME and TS-38 were recorded highest yield and highest Crop Growth Rate during 30-60 DAS indicating that the parameter at that particular stage of growth, has positive impact on seed yield.