Recurrent Restricted Phenotypic Selection for Yield Alters Morphology and Yield of Pensacola Bahiagrass

Abstract

Sixteen cycles of recurrent restricted phenotypic selection (RRPS) have resulted in consistent forage yield increases of space‐planted Pensacola bahiagrass (Paspalum notatum Függe var. saurae Pexodi) plants. The purpose of this study was to assess morphological changes occurring as a result of RRPS for yield. Tests were established in the field in 1988 and 1989. Approximately 100 spaced 1st‐yr plants of each of commercial Pensacola and Cycles 9 and 16 were compared for culm number per plant, racemes per culm, height, leaf length and width, raceme length, plant diameter, plant weight, culm weight, and leaf weight. Differences existed among cycles for all traits. Cycle 16 plants had the highest values and Pensacola plants had the lowest values, except for plant diameter, which decreased as cycles increased. Increases in culm number per plant, plant height, and leaf length increased from Pensacola bahia to Cycle 16 by 32, 44, and 79%, respectively. Mean leaf, culm, and whole plant weights increased by 423, 308, and 382%, respectively. Plant diameter decreased by 15%. Multiple linear regression analysis showed that, in general, plant weight could be closely predicted with two variables, leaf length and number of culms per plant. It was concluded that RRPS for yield has resulted in an increase in size or number of all measured morphological traits while reducing plant diameter. Cycle 16 contained enough variability that progress is expected to continue in future cycles.