HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Busch, R. H. Articles by Luizzi, D. Search for Related Content PubMed Articles by Busch, R. H. Articles by Luizzi, D. Agricola Articles by Busch, R. H. Articles by Luizzi, D.

Effects of Intergenotypic Competition on Plant Height, Days to Heading, and Grain Yield of F₂ through F₅ Bulks of Spring Wheat¹

The effect of intergenotypic competition in F₂ through F₅ bulk generations was evaluated in six tall/semidwarf crosses of spring wheat (Triticum aestivum L.). The bulks had been advanced each generation in competitive yield plots at a commercial production seeding rate. Approximately 100 seeds of each generation (F₂ to F₅) were sampled in each cross, space-planted, and plant height and days to heading, both found to be monogenic in these crosses, were measured on each plant. The three photoperiod insensitive/sensitive crosses had excess numbers of short plants in the F₂ and F₃ but two of the three crosses fit monogenic expectations in the and F₄ and F₅ The sensitive/sensitive crosses fit the expected genetic ratio each generation. A minor shift toward tallness was observed by the F₅ when data from the five homogeneous crosses were pooled. Individual insensitive/sensitive crosses fit the expected genetic ratios for days to heading in F₅, but when pooled over crosses an excess late-heading plants was detected.

Grain yield of the F₂ through F₆ of each of the six crosses across generations did not differ significantly. Correlations of the F₂ bulk yields with yields of through F₆ bulks remained positive with no appreciable decrease. Apparently, changes in bulk populations grown in North Dakota, heterogeneous for plant height and days to heading, were due primarily to genetic segregation, with intergenotypic competition having only minor, but significant, effects. These relatively minor shifts should not inhibit ease of selection for semidwarfism or early heading from competitively grown bulks in North Dakota.

Key Words: Breeding methods • Triticum aestivum L.

² Former professor (Currently: Research geneticist and professor, USDA-SEA-AR, Dep. of Agronomy and Plant Genetics, Univ. of Minnesota, St. Paul, MN 55108), Agronomy Dep., North Dakota State Univ., and graduate student (USAID and Uruguay support; current address: C.I.A. "Alberto Boerger" Est. Exp. Estanzuela, Colonia, Uruguay, S.A.).

Received for publication April 5, 1979.