Farmers' maize yields in S.W. Nigeria and the effect of variety and fertilizer: An analysis of variability in on-farm trials

Methods for Comparing the Yield Stability of Cropping Systems

“…There are several approaches that combine mean and variance of a system, Binswanger and Barah (1980) employ a choice-theoretical approach for combining mean and variance. Pederson (1974), Hlihn (1979, Leon (1986), Nassar et al, (1994, Kang and Magari (1996) and Heyland and MUller (1997) discuss several approaches that combine measures of stability and mean performance. Francis and Kannenberg (1978) proposed a graphical method to evaluate jointly the mean and the coefficient of variation.…”

“…As a result the overview is somewhat state that whether or not intercropping is more dommated by papers related to intercropping, stable than monocropping (in terms of C f^) depends Extensive use has been made of the CAB Abstracts on the mode of interaction between the components database CAB International, Wallingford, United of the intercropping system. Subsequently, Piepho Kingdom), q 995^ showed that under the simple model used by There IS some extensive hterature on the appli-Vandermeer and Schultz, the difference in stability cation of stability analysis to multilines and cultivar depends only on the mixing proportion of the interm««Tr '' nool '''';f''.iy ^^^'«^^d ^y J^^^^" ^^^PP^^ components rather than the mode of mter- (1988), Leon(1994)andSm.thsonandLenne(1996, action. Pearce and Edmondson (1982) consider the so no duplication is necessary here.…”

“…(1992) Boelcke etal. (1991 Bomanetal, (1997) Cattan and Schilhng (1992) Chaudhry andAgarwal (1991) Diepenbrock etal, (1995) Dornescuet al, (1994,1995) Gristinaet al,( 1994) Guertal etal, (1994)" Hildebrand(1984) Jacques and Bacon (1994) Kabakci and Anderson (1995) Li (1993 McNaughton(l992) Mutsaers and Walker (1990) Puschmann(199n Raun etal, (1993) Raun and Barreto (1995) Sarkar and Gosh Dastidar (1994) Sierts (1987), Sierts etal, (1987) Thiaw etal, (1993 "Different year-by-)ocation combinations were regarded as environments without further partitioning year and location effects, ''Papers contain some theoretical developments not reported here in detail, but relevant to stability analysis. 'Papers using Wricke's ecovalence are also listed here, •"These statistics were not computed, but the notion of stability used in the paper is closely related to these measures, 'Authors did not use variance <T, , of yields to assess variation across years, but the range of yields across years, defined as the difference between maximum and minimum yield if a system.…”

Effect of mound height and cassava cultivar on cassava performance under a fluctuating water table

“…Farmer x treatment inleractioncannot be calculated in the conventional way because there was only one replicate per farmer. We therefore used the interaction between trcaunenls and the averaged yield of all lreaUfients ("site mean") for each farmer (Morris 1981;Mutsaers and Walker 1990) as an approximation of treaunent X farmer in-1eraction.…”

Recovery of nitrogen fertilizer by traditional and improved rice cultivars in the Bhutan Highlands

“…In such situations, 'adaptability analysis' provides a good option to determine site effects on the treatments (Hildebrand and Russell 1996;IITA 1991;Mutsaers et al 1997;Mutsaers and Walker 1990). Crop response in terms of grain yield of a particular treatment in a given farmer's field is compared with the environmental index (EI), which is the average of grain yields under all treatments at a given site.…”