ABSTRACT The Interspecific Urochloa recurrent selection breeding programme at CIAT aims to integrate desirable traits such as resistance and tolerance to spittlebugs (Hemiptera: Cercopidae), the main insect pest affecting these pastures in Latin America. Eleven successive cycles of selection were screened for antibiosis and tolerance to Aeneolamia varia nymphs, measured as insect survivorship and plant damage, respectively. The rate of genetic gain was estimated as the slope of the linear function obtained by plotting the best linear unbiased estimates (BLUEs) using historical data across generations. The results show a rapid increase in antibiosis and tolerance to A. varia nymphs. Realized genetic gain for both traits was highly significant ( p < 0.01) and had a negative trend. The annual average rate of plant damage decreased by 2.36%, while insect survivorship decreased by 7.58%. The success in the continuous improvement for spittlebug resistance and tolerance can be explained by the fact that within a breeding cycle, parents are screened and selected based on their resistance and tolerance levels to spittlebug as part of the parental population improvement.
Hernández et al. (Thu,) studied this question.