Seed Yield Characteristics of Alfalfa Populations Selected for Receptacle Diameter and Nectar Volume
1990
Teuber, L. R. | Rincker, C. M. | Barnes, D. K.
Honey bees (Apis mellifera L.) and alfalfa leafcutting bees (Megachile rotundata F.) collect nectar when pollinating alfalfa (Medicago sativa L.). The objectives of this study were to: (i) determine the expression of receptacle diameter (RD) and nectar volume (NE) in the field for subpopulations selected in the greenhouse, and (ii) determine if differences in either RD or NE were associated with seed yield. Bidirectional selection was practiced for RD and for NE in three cultivars. Cycle-2 subpopulations from each source were evaluated at Five Points, CA, and at Prosser, WA for RD, NE, number of seeds/pod, 100 seed weight, number of pods/raceme, and seed yield. Large and small RD subpopulations differed (P ≤ 0.05) at both Five Points (score = 1.9 and 1.1, respectively) and Prosser (score = 3.1 and 1.3, respectively). Small RD subpopulations produced higher seed yields than large RD subpopulations. CUF 101 subpopulations selected for high and low NE differed in NE at both Five Points (15.7 vs. 6.0 μL/100 florets, P ≤ 0.05) and Prosser (62.1 vs. 44.8 μL/100 florets, P ≤ 0.10). Team and Vernal subpopulations selected for high and low NE differed (P ≤ 0.05) for the trait only at Prosser (70.1 vs. 39.8 and 68.7 vs. 32.9 μL/100 florets, respectively). The high NE subpopulation derived from CUF 101 produced more seed (P ≤ 0.05) than the corresponding low NE subpopulation (653 vs. 472 kg/ha, respectively). Greenhouse selection for RD and NE altered these traits under field conditions. Increased NE in alfalfa has the potential for increasing seed production. Joint contribution of the California, Washington, and Minnesota Agric. Expt. Stn. and the USDA-ARS.
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