Document Type

Thesis - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Fred A. Cholick


Fifteen crosses involving three high and three low-yielding hard red spring wheats, (Triticum aestivum L.), adapted inbred lines to the production conditions of South Dakota were used to assess early generation means and variances in identifying bulked populations that produced high-yielding derived lines. In addition, different generations were evaluated to determine which would best identify crosses with the greater potential for producing segregates having high-yielding ability. Traits examined in early generation bulked and spaced-planted populations and derived lines were: 1) grain yield; 2) time to heading; and, 3) plant height. Means and variances of early generation bulked populations were moderately successful in detecting those crosses which produced superior derived lines. The variance was somewhat more effective. Most of the high-yielding and early-heading lines were obtained from crosses identified as superior either by mean, variance or both in F3 and F4 in 1985 and 1986, respectively. None of the parameters, however, was successful in predicting shorter derived lines. Populations producing the largest number of high-yielding derived lines were obtained from crosses with both parents high- yielding. Derived lines with the lower mean yield were from crosses involving low-yielding parents. The proportion of high-yielding derived lines from high X low crosses was the same as from the high x high crosses in 1985. The derived lines obtained from crosses involving SD2861 as one of the parents showed high mean yields and headed early. Crosses involving Guard also showed a large number of high-yielding derived lines.

Library of Congress Subject Headings

Wheat -- Breeding

Wheat -- Yield



Number of Pages



South Dakota State University