PATISSON NAV VA DURAGAYLAR SELEKSIYASI UCHUN BOSHLANG‘ICH MANBA YARATISH

Abstract

F1 hybrids often exhibit more vigorous growth than their parental forms, higher productivity, and greater resistance to diseases. However, this stability is observed only in the first generation. In other words, seeds obtained from an F1 hybrid (i.e., the F2 generation) do not accurately reproduce the traits of their parents. In the F2 generation, trait segregation occurs. Heterosis was originally proposed to be defined as the superiority of a hybrid over its best parental form. More recently, heterosis has often been defined as the superiority of a hybrid over the average performance of its parents. Competitive heterosis is also distinguished, referring to the superiority of hybrids over a standard variety.The latter definition is more suitable for breeding and seed production practices because a heterotic hybrid has practical value only when it significantly surpasses the corresponding regional standard variety. Otherwise, the widespread adoption of the hybrid is not feasible, since hybrid seeds are always more expensive than varietal seeds.