Genotype × Environment Interactions in Sorghum Variety Tests in the Sudan Central Rainlands

Abstract

Estimates of variety x environment interactions for grain yield were obtained from a study involving 16 sorghum varieties grown at the same three locations over a 3-year period. Whereas the variety x year interaction was small and not significant, the variety x location and the variety x location x year interactions were highly significant. Evidence was presented suggesting that the years of testing could be reduced by increasing the number of test locations. T.F.M.7 and Karkatib 4/1/1 were identified as desirable varieties, combining high yield and stability of performance, thereby deserving a place both in commercial production and future breeding programmes.

Allocation of resources in sorghum (Sorghum bicolor L. Moench) yield trials

“…They differ somewhat in the basic approaches, and in the criterion used to evaluate accuracy, e.g. Smith (1938), Schultz (1955), Janick (1961), Sokal & Rohlf (1969, Allen, Comstock & Rasmussen (1978), Kambal & Mahmoud (1978), Russell, Russell, Guthrie, Hallauer & Robbins (1978 and Louw (1979), but have in common a decrease· in experimental error.…”

“…To demonstrate the usefulness of having infonnation on the allocation of resources in this experiment, the methods described by Kambal & Mahmoud (1978) and those of Russell e/ al. (1978) were applied.…”

“…According to the method of Kambal & Mahmoud (1978), practical values of p and r were chosen to determine the value of b required to reach the precision specified. The value specified was a standard error of the mean, Sx = 2,97, being 10% of the mean yield of the relevant experimental material.…”

“…In the components of variance analysis of Kambal & Mahmoud (1978) an increase in the number of plants alone was not adequate to achieve the desired criterion of ~ = mean yieldllO = 3 g. Due to the large cOmponent of variation observed for the genotype x block interaction (S~ = 39,81), the number of plots first had to be increased to at least six. With six blocks, at least 20 plants per row were required to achieve the required critetjon.…”

Physiological basis for transgressive yielding in bean-maize intercrops

“…He concluded that linear regression methods, if inappropriately applied, are an oversimpli fication of the response of genotype to environment and that multi variate techniques may be a useful alternative when the environments differ by more than one factor. Kambal and Mahmoud (1978) Trenbath (1974a) found no evidence that crop mixtures demonstrated greater intrin sic stability than did the more stable component monoculture.…”