Correlation and Path Coefficient Studies of Yield and Yield Related Characters in Tannia (Xanthosoma sagittifolium (L.) Schott) Genotypes

摘要

Tannia is the sixth most important root tuber crop for food, feed and industrial applications worldwide. However, the crop is neglected and unexploited in Ethiopia even though large gene pool is available in south and southwest Ethiopia in farmers' field and homesteads. So far no improved varieties are available and its national productivity (7.9 t ha-1) is far below the crop's potential (30-60 t ha-1)- For effective selection of genotypes, understanding of the magnitude and the interrelationship ofyield and yield related traits is excellent tool for determining the direction and number of characters to be considered in the crop improvement program. Hence, the objectives of the present study were to determine the genetic relationship and identify traits that have direct and indirect effect on yield of tannia. So, a total of sixty four tannia genotypes were studied based on 16 quantitative characters at Jimma Agricultural Research Center during the 2013/14 cropping season. Sixty two of the genotypes were collected from south, south western and western parts of Ethiopia and two were introduced from Cuba, laid out in 8x8 simple lattice design. The data were subjected to correlation and path coefficient analysis. The correlation study reveals that majority of the characters were positively correlated with each other. Total yield was positively and significantly correlated with corm weight and cormel weight both at phenotypic (r_p = 0.825; r_p = 0.957) and genotypic level (r_g = 0.859; r_g = 0.954),respectively. The path coefficient analysis showed that cormel fresh weight (0.549) and corm weight (0.55) exerted the maximum direct positive effect on total yield per plant. Also, plant height, plant canopy, corm and cormel length, cormel fresh weightand corm weight exerted positive direct and indirect effect which indicates that these characters could be effective for selection and further yield improvement program of tannia.