Relationships among agronomic traits and seed yield in pea

the evaluation of selection criteria using correlation coefficients, multiple regression and path analysis was carried out for a period of two years on forty pea genotypes. the correlation analysis revealed that grain yield had genotypic relationships with numbers of pods, seeds per plot, length of the internodes and plant height in 2007 and also with grain diameter, length and width of leaflets and number of nodes at the first pod in 2008. the highest positive direct effects in 2007 were length of the internodes (0.68), seeds per plot (0.38) and numbers of pods (0.26). length leaflets exhibited a negative direct effect (-0.46). the highest positive indirect contribution of plant height mediated by length of the internodes was 0.50. the highest negative indirect contribution was pod length via length of the internodes (-0.35). in 2008, the highest positive direct effects were seeds per plot (0.67), width leaflets (0.33) and numbers of pods (0.25). length leaflets presented the highest negative direct effect (-0.34). the indirect effects were observed via seeds per plot, length and width leaflets; therefore numbers of pods and seeds per plot can be used for indirect selection. the parameter estimated showed that number of pods and seeds, and pod length determined the yield during 2007 and number of pod and seeds, and grain diameter during 2008. the r2 values for both models were 0.60 and 0.89 respectively. the number of pod and seeds per plot were the main components of seed yield, having the maximum direct effects on this trait. these results might be used as selection criteria in order to increase the selection efficiency in pea breeding programs.