Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 16, 2001
Publication Date: N/A
Interpretive Summary: A better understanding of the physiological components which affect yield potential in rice would help breeders develop better selection tools for developing high yielding rice cultivars. An evaluation of 13 breeding lines developed from a cross of Lemont and Teqing cultivars was used to identify several physiological traits which influenced yield potential. The amount of sugars that are present in the rice plants' leaves and stems and which can be mobilized to the developing grain was monitored throughout the growing season. High yielding lines were associated with low amounts of sugars in developing grain near flowering and in the stems near harvest. This indicated that higher yielding genotypes must have a large number of grain sinks that can receive the mobilized sugars. A build up of sugars in the developing grain head early in the season or in the stems late in the season will indicate that these lines will not have high yield potential.
A study was conducted to determine how various yield components in rice are affected by total nonstructural carbohydrate and biomass accumulation patterns during the growing season. Thirteen recombinant inbred lines that had been derived from a cross of the U.S. cultivar, Lemont and the high- yielding Chinese cultivar, Teqing were evaluated across two field seasons in Beaumont, TX. The inbred lines were classified according to high and lo groups for tillering ability, grain weight, panicle node number and panicle size. High grain weight genotypes were associated with high leaf weight at heading and low stem and leaf weight at harvest. High grain weight genotypes also had low total nonstructural carbohydrates in the panicle at heading and in the stem at harvest. These results indicate that breeders can select for high yielding genotypes by identifying breeding lines which have high leaf biomass at heading that allows for greater photosynthetic capacity and high remobilization from the stems and leaves prior to harvest. High concentrations of total nonstructural carbohydrate in the panicle at heading or in the stems at harvest may indicate a reduced sink capacity which limits grain yield.