Abstract

This study aimed to evaluate the growth performance and yield of CMD-resistant cassava hybrids under experimental field conditions at the National Corn and Sorghum Research Center, Klang Dong Subdistrict, Pak Chong District, Nakhon Ratchasima Province, Thailand. Six CMD-resistant cassava hybrid lines produced through a rapid multiplication system (x20) were evaluated. Four lines were derived from the Thai breeding program (98-51, 98-112, 98-113, and 98-118), while two lines (CR24-16 and CR13-8) were introduced from the Centro Internacional de Agricultura Tropical (CIAT). Cuttings of two commercial Thai varieties, Huay Bong 90 and Huay Bong 100, were planted as checks. The experiment was arranged in a randomized complete block design (RCBD) with three replications, each consisting of 36 plants per genotype. Planting was conducted in April 2024. Growth parameters were recorded at 4 and 6 months after planting (MAP), including plant height, canopy width, stem diameter, number of lateral branches and first branching height. At 4 MAP, Huay Bong 90, Huay Bong 100, genotypes 98-51, 98-112, 98-118, and CR13-8 exhibited significantly greater plant height than CR24-16. Genotypes 98-51 and CR13-8 showed the largest stem diameter, while CR24-16 produced the highest number of lateral branches. At 6 MAP, plant height did not differ significantly among hybrid lines. However, genotype 98-113 showed the greatest stem diameter, followed by 98-51. Genotype CR13-8 exhibited the first branching height. Yield and starch content were evaluated at 10 MAP. Genotype 98-113 produced the highest fresh root yield (4.59 kg /plant), followed by Huay Bong 100, 98-51, and Huay Bong 90. The highest starch content was observed in Huay Bong 90 (30.83%), followed by Huay Bong 100, 98-113, and 98-112.