INHERITANCE OF ABIOTIC STRESS THROUGH COMBINE SELECTION APPROACH IN RICE

Abstract

Five rice varieties of diverse Phenotypes, F; and F2 population of the crosses Zirasail x Nerica-4, Hobigonj-6 x Nerica-4, Pariza X Nerica-4, BRRI Dhan -28 x Nerica -4 were grown in the field research field of Hajee Mohammad Danesh Science and Technology University, Dinajpur-5200. To study the maximum growth occurrence of root xylem vessel number, to investigate the gene systems of root and shoot characteristics related to drought avoidance mechanism.The varietal differences for root xylem vessel number was observed at 20 days after sowing and the maximum growth occurred at 40 days after sowing. The root and shoot characters were generally controlled by polymeric genes with additive and/or dominance effects. The additive gene affects was important in the expression of root xylem vessel number. Dominant alleles controlled root dry weight, Shoot dry weight, Root length, and Tiller no. and plant height. Dominant alleles controlled shallow roots of Pariza, Zirasail and hobigonj -6. Additive and dominant gene effects were important in the inheritance of root xylem vessel number, root thickness and root- shoot ratio. Heterosis and heterobeltiosis were observed for most traits. heterobeltiosis was positive for the trait root dry weight, root length and tiller number. Heterobeltiosis was positive for the trait root length, root thickness, root-shoot ration, tiller number and plant height. The broad sense heritability estimates were relatively high for root xylem vassel number, root-shoot ratio, root thickness, root dry weight and low to moderately high for root length, shoot dry weight, plant height and tiller number. Results indicated that the root characteristics such as thick and long root with high xylem vessel number and area can be studied efficiently in early segregating generations. Above ground plant characters like height, tiller number and shoot weight appear to be good indicators of a the extent of the development of a root system. The Parents obviously differed greatly in their genetic make ups. Refined studies are needed to assess the genotype environment interactions. Root length was positively associated with root-shoot ratio and plant height. Root thickness was positively and significantly correlated with root dry weight, shoot dry weight, tiller number. Root dry weight positively correlated with shoot dry weight, Root —shoot ratio, plant height and tiller number. Shoot dry weight was positively correlated with root-shoot ratio, tiller number and plant height. Root —shoot ratio was positively correlated with tiller number and plant height. Plant height was positively correlated with tiller number. On the other hand, Root xylem vessel number was negatively and significantly correlated with root length, root dry weight, shoot dry weight, root-shoot ratio, plant height and tiller number. Root length was negatively and significantly correlated with root thickness, shoot dry weight and tiller number. Root thickness was negatively and significantly correlated with rootshoot ratio and plant height.