AN EVALUATION OF AN EARLY GENERATION YIELD TESTING PROCEDURE IN TRITICUM AESTIVUM

Abstract

The effectiveness of assessing unreplicated F3 lines for yield in a wheat (Triticum aestivum L.) cross was determined by the regression and correlation between F3 lines and related F4 bulk means, and between F3 lines and related F5 family means. The correlation and regression coefficients obtained between F3 line and F4 bulk mean yield expressed as a percentage of adjacent control were 0.59** and 0.39**, respectively. The correlation and regression coefficients obtained between F3 line and F5 family mean yield expressed as a percentage of control were 0.56* and 0.39*, respectively. By growing a large sample of the progeny of each F3 genotype adjacent to a control, it was possible to discriminate among F3 lines for heritable quantitative differences.

The effectiveness of early generation (F3) yield testing and the single seed descent procedures in two cowpea (Vigna unguiculata (L.) Walp.) crosses

“…Thus the relatively wide interrow spacing along with replications helped in reducing the competition effects . Similar correlation studies have between conducted in several self-pollinated crops such as soybeans, wheat, oats and barley but the various ranges of observed intergeneration correlations have been such that no firm conclusions can be drawn as to the effectiveness of early generation selection for yield (BRIGGS & SHEBESKI, 1971 ;DE PAUW & SHEBESKI, 1973 ;KNOTT & KUMAR, 1975 ;O'BRIEN et al ., 1978 ;WHAN et al ., 1981) . The resuts of this study, however, clearly indicated that early generation (F 3) selection for yield can be effective in cowpeas .…”

Marker-assisted selection in segregating generations of self-fertilizing crops

“…However, early generation selection has generally been found to be ineffective for conventional phenotypic selection (McGinnis and Shebeski 1968;Knott 1972;Depauw and Shebeski 1973;Hanson et al 1979). This is in agreement with our results that phenotypic selection in early segregating generations leads to smaller genetic responses and lower frequencies of superior genotypes.…”

Proposal for an unambiguous designation of material used in breeding programmes for self-fertilizing crops

“…Thus, more or less cryptic descriptions like 'F, family mean yield were correlated to F, derived line yield' (DE PAUW & SHEBESKI, 1973) are used. Thus, more or less cryptic descriptions like 'F, family mean yield were correlated to F, derived line yield' (DE PAUW & SHEBESKI, 1973) are used.…”

“…According to this notation the phrase 'regression of F, line value and F, bulk mean' (see DE PAUW & SHEBESKI, 1973) may be replaced by 'regression of F,,, mean yield on F3,2 mean yield'. Similarly, 'regression of F, line value and F, family mean' can be replaced by 'regression of F,,, mean yield on F 3,2 mean yield'.…”