Effects of selection for more vigorous seminal roots in two cross populations of oat (Avena sativa L.)
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Three steps of multi stage selection for more vigorous seminal roots were done in two cross combinations of oat. The total length of roots (TRL) was measured in seedlings of the F2 , F3 and F4 generations grown in filter paper rollers. On average, the finally selected F5 (or F6 ) progenies distinguished by 7 11% improved rooting ability than their midparents. Transgressive forms were selected only in one cross combination. Coefficients of realized heritability for TRL were low and ranged from 0.08 to 0.42 indicating a relatively high proportion of non additive gene effects in the variance of TRL. Tolerance of the F6 progenies to water and nutrient limitations was evaluated in pot and field experiments. Correlated selection effects were dependent upon initial cross combination. Only progenies from one cross combination exhibited an improved drought tolerance at the 8 9 Feekes' stage. The both enhanced rooting and decreased S : R ratio of the F6 progenies correlated with their improved tolerance to reduced P supply at the 4 leaf stage. However, no significant consistence occurred between indices of the tolerance to reduced nutrition at the vegetative growth and those at field maturity. Performed root selection identified more frequently high yielding genotypes with less stable grain yield. No progenies were obtained that outperform their parents under low input conditions. It was emphasized that root selection should be accompanied by selection for integrated response components.
Publication order reference
A.G.Gorny, Institute of Plant Genetics, Polish Academy of Sciences, Strzeszynska 34, 60-479 Poznan, Poland.