Cytoplasmic Effects on Plant Traits in Interpecific Matings of Avena

Abstract

Sixty populations of 20 oat lines each, representing reciprocal crosses of the BCo, BC1, and BC2 of all possible matings among five Avena sterilis L. accessions and two A. saliva L. cultivars, were evaluated in a field experiment for grain yield, straw yield, harvest index, heading date, plant height, unit straw weight, and vegetative growth index. On average, A. sterilis cytoplasm delayed heading date by 1.1 days and increased grain yield by 250 kg/ha or 10%. The cytoplasmic effect on heading date was consistent over backcross generations. Average grain yield was significantly greater for lines having A. sterilis cytoplasm in all BC generations, but the differences were less consistent than those for heading date. Straw yield, plant height, unit straw weight, and vegetative growth index were increased significantly by A. sterilis cytoplasm in the BCo, but these advantages decreased by BC1 and disappeared by BC2. Avena sterilis cytoplasm had no effect on harvest index in BCo, but by BC2, it had elevated this trait by 1.1%. Avena sterilis cytoplasm showed no interactions with matings for heading date, which indicates that the effect of the cytoplasm on this trait was direct. Significant interactions of A. sterilis cytoplasm with matings indicate that the grain yield increases were due to specific favorable interactions between A. saliva nuclear genomes and cytoplasms. The interaction between level of backcrossing and cytoplasmic effect for straw yield, plant height, unit straw weight, vegetative growth index, and harvest index probably resulted because of interactions between A. sterilis cytoplasms and A. sterilis nuclear genes, solely, or particular combinations of A. sterilis and A. sativa nuclear genes. These results suggest that breeders may be able to improve the potential for productivity of oats by using diverse cytoplasms. Additionally, cytoplasmic diversity might make oats more stable in production over diverse environments.