Recurrent selection for increased yield in soybean with the aid of genetic male sterility using three selection methods
Abstract
Recurrent selection has not been a common breeding method for soybean (Glycine max (L.) Merr.) because of the difficulty of making the hundreds of crosses needed in each cycle. The use of male sterility was suggested a number of years ago to help solve this problem. The principal objective of this study was to determine the effects of recurrent selection methods on the mean yield and maturity of a population when selecting among individual space-planted S$\sb0$ soybean plants for three yield-related traits: (1) yield per se, (2) apparent harvest index, and (3) a selection index that involves regression yield on maturity date in an effort to restrict population maturity shifts. The original intermating population was a combination of the variety Century and two F$\sb2$ populations segregating for male sterility. The Cycle 0 population was grown the following year and three separate populations were then formed by selecting for yield (YLD), apparent harvest index (AHI), and maximum deviations from the regression of yield on maturity (REG). The selection intensity throughout the study was 20%. Each population was carried through three cycles of selection. The YLD population showed a moderate increase in yield of nearly 3 g plant$\sp{-1}$ cycle$\sp{-1}$ along with a significant shift toward lateness of nearly 4 days cycle$\sp{-1}$. The AHI population had a moderately large decrease in yield of about 4.5 g cycle$\sp{-1}$ while maturity was moved slightly earlier. There was very little change in AHI. The REG population had a yield increase of 5.7 g cycle$\sp{-1}$ while being shifted toward later maturity by less than 1 day cycle$\sp{-1}$. It was concluded that selection among S$\sb0$ plants using the selection index of yield regressed on maturity could be effective in increasing yields without causing a significant shift in maturity. Selecting for yield alone caused an unacceptable shift toward lateness while selection for AHI was ineffective for increasing yield or AHI.
Degree
Ph.D.
Advisors
Wilcox, Purdue University.
Subject Area
Agronomy
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