Genetic variation for biomass and residue production in lentil: II. Factors determining seed and straw yield

Understanding the influence of vegetative and reproductive traits in lentil (Lens culinaris Medik.) on biomass production and seed yield would facilitate cultivar improvement. The objectives of this study were (i) identify and evaluate the morphological changes that have taken place during past cultivar improvement efforts, and (ii) quantify the effect of rainfall on seed and straw production. Seven breeding lines and three checks were evaluated at Pullman and Farmington, WA, and Genesee, ID, from 1993 to 1995 for vegetative growth period (VGP), generative growth period (GGP), crop growth rate (CGR), seed growth rate (St.GR), straw growth rate (St.GR), and partitioning coefficients for seed (p) and straw (q). Results indicated that past cultivar improvement efforts have achieved higher seed yields by (i) shorter generative and vegetative growth periods, (ii) greater rates of crop and seed growth, (iii) higher seed partitioning coefficients, and (iv) a moderate response to rainfall. Greater straw yields have been achieved by (i) longer generative and vegetative growth periods, (ii) greater crop and straw growth rates, (iii) a higher straw partitioning coefficient, and (iv) a greater response to rainfall. Simultaneous improvement of straw and seed yields is possible within existing lentil germplasm.