Study of relationships between seed and forage yields and their components in red clover (Trifolium pratense L.)

Red clover (Trifolium pratense L.) is one of the important perennial forage legumes that grows naturally in Iran. In order to evaluate relationships between seed yield, forage dry matter yield and their components, 9 accessions of the species were planted and evaluated using a completely randomized block design with three replications in Alborz research center, Karaj, Iran during 2002-2003. The results of correlation analysis showed positive and significant relationships, between forage yield and leaflet lamina area, internode length, petiol length, canopy height, persistency and number of stems per plant. Seed yield had positive and significant relationships with number of stems per plant, persistency and number of seeds per inflorescence. Using regression analysis, the important traits were detected. Number of stems per plant, number of seeds per inflorescence, persistency, number of inflorescences per stem, internode length and number of florets per inflorescence were the important triats for forage yield (R²=99). Using path analysis, persistency and internode length had direct positive effects on forage yield. Number of seeds per inflorescence and number of inflorescences per stem had direct and negative effects on yield, but increased forage yield indirectly through improving persistency and internode length. It was concluded that persistency and internode length were the important triats for improvement of red clover varities. Number of seeds per inflorescence, 1000 grains weight, growth habit, number of inflorescences per stem, number of florets per inflorescence were the important triats for seed yield (R²=98). Using path analysis number of seeds per inflorescence had direct significant effect on seed yield. It was also concluded that number of seeds per inflorescence were the important traits for breeding seed yield in red clover. Although, 1000 grains weight had negative and direct effect on seed yield, indirectly through increasing number of seeds per inflorescence improved seed production.