Genotype-dependent and heat-induced grain chalkiness in rice correlates with the expression patterns of starch biosynthesis genes.

Starch biosynthesis is a complex process underlying grain chalkiness in rice in a genotype-dependent manner. Coordinated expression of starch biosynthesis genes is important for producing translucent rice grains, while disruption in this process leads to opaque or chalky grains. To better understand the dynamics of starch biosynthesis genes in grain chalkiness, six rice genotypes showing variable chalk levels were subjected to gene expression analysis during reproductive stages.

Genetic variation and association mapping of silica concentration in rice hulls using a germplasm collection.

An association analysis on the genetic variability for silica concentration in rice hulls was performed using a "Mini-Core" set of 174 accessions representative of the germplasm diversity found in the USDA world collection of rice. Hull silica concentration was determined in replicated trials conducted in two southern states in the USA and was analyzed for its association with 164 genome-wide DNA markers. Among the accessions, the average silica concentration ranged from 120 to 251 mg g(-1).

Mediation of partial resistance to rice blast through anaerobic induction of ethylene.

ABSTRACT The correlation between anaerobic soil conditions and increased resistance to rice blast disease has long been observed without benefit of an adequate explanation. We researched flood depth, dissolved oxygen (DO), and ethylene relative to expression of partial blast resistance in cvs. M-201, Newbonnet, LaGrue, Mars, and Cypress.

An integration of photosynthetic traits and mechanisms that can increase crop photosynthesis and grain production.

The hypothesis we propose is that during photosynthesis the balance between potentially detrimental and beneficial photochemically induced events can be tipped beneficially toward increased photosynthesis and toward increased crop yield. To test this hypothesis a procedure has been devised with the rice plant, Oryza sativa, that has resulted in increasing both canopy photosynthesis and rice grain yield. Two elite rice varieties selected independently in the contrasting environments of either South China or Texas, each with distinct photosynthetic traits, were crossed to produce a hybrid with an increased canopy photosynthesis and grain yield that is regularly 20 to 22% higher than the mid-yields of the parents.