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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #105510
Title: GENE ACTION OF BIOMASS PARTITIONING IN ALFALFA DURING THE SEEDLING YEAR

Author
item MARQUEZ-ORTIZ, JESUS - INIFAP CELALA MEXICO
item JOHNSON, LAUREN - CAL WEST SEEDS
item BARNES, DONALD - RETIRED ARS EMPLOYEE
item Lamb, Joann

Submitted to: Agrociencia Magazine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Slow progress has been made in improving forage yield in alfalfa. Most yield increases have been due to increased pest resistance and plant longevity. Unfortunately, pest resistance does not contribute to greater yield when the pests are not present. We proposed that selecting individual alfalfa plants with greater plant top or above ground weight compared to root or below ground weight could increase forage yield in alfalfa. This method of selection showed great promise for increasing above ground yield in alfalfa. Therefore, programs creating improved alfalfas with multiple pest resistance, enhanced longevity, and increased yield should be possible using our new selection method. This new method should produce alfalfa varieties with increased forage yields resulting in greater economic return for producers in years when pest infestations are minimal.

Technical Abstract: The use of a harvest index to assess biomass partitioning to increase yield in alfalfa (Medicago sativa L) has received little attention. The objectives of this research were to determine the effect of locations on harvest index, and gene action of such an index in alfalfa. Progenies from design II matings and diallels were evaluated at Rosemount and Becker, MN. The experimental unit was 12 plants at 2.5 cm spacings within a 30 cm row segment. Progenies were evaluated in August, September, and October for shoot yield and in October only for fall dormancy and crown and root mean dry matter per plant. Shoot, crown, and root dry weights were used to calculate a harvest index as the ratio shoot/(shoot+crown+root), based on dry matter weight for each of three and total harvests. Total harvest index means ranged from 0.56 to 0.63 and were affected by locations. Design II and diallel analyses suggested that additive and non-additive effects were important for the total harvest index. Results indicate that selection for the seasonal harvest index for increased herbage yield should be effective at either location.