Biomass Yields for Kenyan Brachiaria Grass Ecotypes Grown Under Varying Water Stress Conditions

Abstract

Brachiaria (syn. Urochloa) grass is an important forage for livestock production in Kenya. However, the suitability of Brachiaria grass as a feed option will require the
identification of locally adapted and high yielding ecotypes for breeding. Some of the Brachiaria varieties developed from other countries and introduced in Kenya are susceptible to diseases and drought. The aim of this study was to evaluate various Kenyan Brachiaria grass ecotypes for biomass production under different soil moisture stress conditions. A screenhouse trial was established in April 2021 with thirty-two Kenyan Brachiaria ecotypes and three varieties at Kenya Agricultural and Livestock Research Organization (KALRO), Katumani. Actively growing rooted tillers of each ecotype were transplanted in plastic pots using forest soil, sand and manure at a ratio of 3:2:1. The pots were subjected to four water stress treatment conditions during the growing period. The plant height, number of tillers per plant and above
the ground biomass yield was determined after 28 days of stress treatment. There was large genotypic variability in the studied traits of Brachiaria genotypes in both non-stressed (control) and drought stressed plants. Drought stress significantly reduced all the traits studied with 25% Field Capacity being the most severe. Ecotype N13 was the tallest while Kisii produced the highest number of tillers. There was a strong positive correlation between the number of tillers and biomass yield. Kakamega, Kisii and Busia genotypes were the most productive under severe moisture stress and thus may be useful in breeding strategies for improved forage yield to increase livestock productivity.