• Carbohydrates in Germination Salt Tolerant and Non-Salt Tolerant Alfalfa Seed

      Dobrenz, A. K.; Poteet, D. C.; Miller, R. B.; Smith, S. E.; Ottman, Michael; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-09)
      Alfalfa which is extremely salt tolerant during germination has been developed by researchers at the University of Arizona Carbohydrates were analyzed in the original parental gemiplasm 'Mesa- Sirsa' and Cycle₅Syn₂ and Cycle₈Syn₂ seed to determine why this seed could germinate in extremely saline conditions. Raffinose and sucrose were both significantly higher in the salt -tolerant germplasm compared to the parental germplasm; however, the magnitude increase of these free sugars was not sufficient to explain the increased ability of the seed to absorb water in a stress environment. The galactomannan content was not different among the alfalfa germplasms.
    • Performance of Middle-Eastern Alfalfas Using Traditional and Southwestern Harvest Management Practices

      Al-Doss, Abdullah, 1963-; Smith, S. E.; Conta, D. M.; Ottman, Michael; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-09)
      The nondormant alfalfa cultivars now grown in Arizona trace largely to a small number of alfalfas introduced from the Middle East. Middle Eastern alfalfas regrow rapidly primarily from crown shoots following harvest and produce high yields during late fall, winter and early spring. Harvest management may have a significant effect on the persistence and yields of Middle - Eastern alfalfas under Arizona conditions. In the Middle East, alfalfa is frequently harvested at the bud stage and little stubble is left. In this experiment we compared the yield and persistence of Middle Eastern alfalfa ecotypes under traditional Middle - Eastern (bud stage + 2 cm stubble) and Southwestern harvest management (10% bloom + 10-15 cm stubble), and a regime with elements of both primary systems (bud stage + 10-15 cm stubble). Only slight differences in yield or persistence were observed between the management systems in the most nondormant entries, however, some ecotypes produced significantly more forage than Lew. No apparent advantages were noted for harvest leaving 2 cm stubble. Elevated yields of high quality forage would be produced with bud stage harvest and 10-15 cm stubble in most Middle Eastern ecotypes.
    • Release of a Nondormant Alfalfa Population with Improved Forage Yield in Saline Environments

      Johnson, D. W.; Smith, S. E.; Conta, D. M.; Dobrenz, A. K.; Ottman, Michael; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-09)
      Salinity is a persistent problem for alfalfa growers in Arizona that will likely worsen over time. Plant breeding may offer a relatively low-cost short-term solution: varieties bred to remain productive in the presence of moderate levels of salinity. We have developed and released AZ-9ONDC-ST, a broad - based, nondormant alfalfa population with increased forage yield in greenhouse trials under moderate NaCl stress. AZ-90NDC-ST was derived from two cycles of selection for increased forage yield under NaCl stress from AZ-88NDC a composite nondonnant population previously released by the experiment station. AZ-90NDC-ST was developed to provide a source of alfalfa with increased forage production under moderate salt stress and is the only population with these characteristics in existence. This population, which has been made available to the alfalfa breeding community, will provide the basis for improved high yielding and pest- resistant varieties for use in areas in subject to salinity stress.