Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
EFFECT OF HETEROSIS, CYTOPLASM TYPE, AND SEED SOURCE ON SEEDLING COLD TOLERANCE IN GRAIN SORGHUM (NEBRASKA)
Abstract
Four field experiments were conducted at two locations in Nebraska in 1982 to investigate the genetic factors and seed quality traits involved in seedling cold tolerance of grain sorghum. The planting dates at Sidney and Mead were more than three weeks earlier than normal, and the material was subjected to cooler than normal conditions. Traits observed were stand counts, a visual rating for vigor, and average dry weight of plants harvested at approximately the ten leaf stage. Twenty-eight parents and F(,1) hybrids were used to quantify heterosis and compare sterility-inducing and fertility-inducing cytoplasms; the experimental design was a randomized complete block with subplots. Heterosis was strongly expressed for all traits. Cytoplasmic and nuclear interactions accounted for different cold responses in only a few genotypes, but in one inbred the sterility-inducing form consistently out-performed the fertility-inducing form. The visual rating variable correlated well with both average dry weight and the plant counts. Deviation in results from the other variables indicated that stand counts made before 30 days after planting were not representative. Percent viable seedlings and average dry weight from an optimum temperature vigor test in a growth chamber were significantly correlated with the field results at Mead but not at Sidney. In a second experiment, the material differed with respect to the location of production in the previous season and in whether or not the panicle had been covered with a pollination bag or left uncovered during the grain filling period of seed production. The hybrid Martin X DA3494 was produced at Glenvil and Mead, and no differences existed due to location. The hybrid CK60 X DA3494 was produced at Glenvil, Mead, and North Platte, and seed from Glenvil was superior to the other two. For the eight hybrids tested, the comparison between panicles covered or uncovered was nonsignificant. There was little to suggest that the presence or absence of a pollination bag during the grain filling period contributed to cold tolerance of the seed in the following season. In a third experiment, the treatments were the quadrants of the panicle during the seed filling period. Upon harvest the previous year, the seed was divided into four positions using the upper and lower half and the north and south aspect. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI
Subject Area
Agronomy
Recommended Citation
MATTHEWS, RALPH VINCE, "EFFECT OF HETEROSIS, CYTOPLASM TYPE, AND SEED SOURCE ON SEEDLING COLD TOLERANCE IN GRAIN SORGHUM (NEBRASKA)" (1983). ETD collection for University of Nebraska-Lincoln. AAI8328182.
https://digitalcommons.unl.edu/dissertations/AAI8328182