Stay-green In Maize:Evaluation And Genetic Effect Analysis

Stay-green is a general term applied to a variant in which senescence is delayed, compared to a standard reference genotype, and is regarded as a desirable character closely related to yield, forage character, disease and pest resistance. Study the method of stay-green evaluation and its genetic mechanism has the practical significance for maize germplasm innovation and breeding new stay-green varieties.This experiment used20hybrids combinations obtained by6inbred lines with different stay-green characteristics, and two6-generation crosses between two stay-green lines and two non-stay-green lines. The stay-green trait of the20materials is described in terms of absolute green leaf area duration, relative green leaf area duration and relative green leaf area at maturity. and analyze the relations of stay-green traits and the relations of stay-green trait with the yield and other agronomic traits. In order to study the inheritance of stay-green, two crosses between two stay-green lines,and two non-stay-green lines were analyzed by quantitative inheritance method. The main results are as follows:1. Stay-green is related with many traits, such as relative green leaf area at maturity, leaf area duration, absolute leaf area duration and relative leaf area duration, green leaf number at maturity and chlorophyll content at maturity, the principal component analysis showed that these traits can be divided into three principal components. And use Comprehensive trait for standard to classify maize breeds was better than that one single trait it can be better reflected the differences of stay green in maize.2. The descent speed of number of green leaf, green leaf area, elative green leaf area at maturityof non-stay green hybrids after post-flowering time were much faster than those of stay-green hybrids materials. The absolute green leaf areas duration and relative green leaf areas duration of non-stay green inbred line were significantly lower than those of stay-green hybrids. the green leaf number at maturity were extremely positive correlated with stay-green degree, leaf area duration, absolute leaf area duration and relative leaf area duration, and it’s positive correlated with leaf area duration, so the number of visual retained green leaves at physiological mature to roughly estimate the stay-green of hybrid combinations.3. Maize stay-green is quantitative traits, the additive and dominant gene effect as well as gene interactions could be found in the inheritance of stay-green. this study shows that additive and dominant effects were positived, and this was good for offsprings. In some combinations,the dominant effect was greater than additive effect, performan as overdominance. The range of broad heritability of stay-green was from47.93%to65.72%and ratio additive genetic variance and genetic variance ranged from42.62%to55.72%4. The stay-green trait is very important to improve yield. leaf area duration absolute leaf area duration and relative leaf area duration were extremely positive correlated with100-kernal weight, The correlation coefficient were0.601,0.532and0.736, respectively. absolute leaf area duration and relative leaf area duration were extremely positive correlated with Panicle weight, the correlation coefficient were0.676,0.746and0.611, respectively...