| dc.description.abstract | The effect of water limitations on Hard Red Winter Wheat (HRWW) production is a major concern for the wheat industry throughout the Southern Great Plains. Average HRWW yield was compared between irrigated and rainfed conditions at four locations within the High Plains region of Texas and New Mexico, and then screened among 19 HRWW cultivars and experimental lines to select the best growth performance under three levels of water limitations under greenhouse condition. From the 19 HRWW cultivars, nine were selected to undergo further screening under the same treatment conditions for yield characteristics. Finally, genetic diversity for these 19 HRWW cultivars and experimental lines were analyzed by using genotyping by sequencings (GBS) for genetic relatedness. Results from the panhandle of Texas showed that CJ, TX02A0252, and Ruby Lee, had the highest rainfed/irrigation yield ratio. On the other hand, Iba, Billings, and Mace had the lowest rainfed/irrigation yield ratio. Under greenhouse condition, results under severe water limitation in preliminary evaluation of the 19 cultivars and experimental lines showed that Byrd, Ruby Lee, TAM 113, and Duster showed higher average of seed weight whereas Endurance, Chisholm, and Gallagher showed lower average in the same trait across two cycles of growth and development. In final screen, results showed that Gallagher, Ruby Lee, and Endurance showed higher average seed weight whereas Jagger, Byrd, and Cedar showed lower average seed weight. The result of discriminant analysis showed that seed number and spike number were the most important traits that contributed to discriminant among 19 HRWW cultivars and experimental lines across all cycles of growth and development. The Neighbor joining tree divided 19 HRWW cultivars and experimental lines into five groups consisting of group one Iba, Duster, OK12621, OK10126, Cedar, Garrison, and Hatcher, group two Byrd, TAM 112, TAM 113, and TAM 111), group three Endurance and Ruby Lee, group four Chisholm and Gallagher, and group five Jagger, OK Bullet, Bentley, and OK11D25056. The higher genetic similarity was found between Duster and Iba whereas the least similar was found between Jagger and Hatcher. | |
