Ovule Number and Flower Size in Pea (Pisum sativum L.): Variation, Heritability, and Correlation with Some Components of Productivity

Abstract

The seed yield in pea (Pisum sativum L.) depends on numerous environmental and genotypic factors. The ongoing climate changes draw one’s attention to genetics and variation of underexplored reproductive traits. This study focuses on ovule number (ON) and flower size expressed as a length of flag petal (FL), in terms of their heritability, variability, and correlation with 1000 seed mass (TSM), seed number per pod, and seed/ovule ratio. A set of pea accessions was planted over several years in field conditions. Some of these accessions were also grown in a glasshouse. The chosen values were scored on living plants or while harvesting seeds. Nonparametric statistical methods were applied. Heritability of ON and FL was studied in five hybrid F1/F2 combinations. We found a relatively low (ca. 0.5) broad sense heritability of both ON and FL. Among other traits, TSM and ON reproduced best over the years. FL exhibited no reproducible correlations with other traits and cannot be used as a predictor of productivity. Water deficit and heat stress reduce seed yield in pea due to both seed abortion and development of fewer ovules. The differential and heritable ability to retain ON may become a basis for breeding pea cultivars adapted to changing climate.