A Diagnosis of Yield‐Limiting Factors on Probe Genotypes for Characterizing Environments in Winter Wheat Trials

Abstract

decreases as KN increases according to an hyperbolic relationship. Applying this to winter wheat, Leterme et Genotype ϫ environment interaction is fully analyzed when genoal. (1994) fully described how to interpret this relationtypes and environments are well characterized. Probe genotypes were studied in a simplified crop diagnosis to show how variates of yield ship between TKW and KN. components can strengthen characterization of environments by usual Because these two yield components are developed indicators of yield-limiting factors. The objective of this study was to over two distinct crop development periods, (from sowdetermine the main limiting factors of yield and to analyze their effects ing to flowering for KN and after flowering for TKW), in wheat (Triticum aestivum L.) trials. Fixed genotypes (Talent, Soisthis allows identification of when the limiting factors sons, Camp-Ré my, and Arminda) were studied as probe genotypes occur. Their intensity is determined by comparison to at five experimental stations of the Institut National de la Recherche reference values considered as threshold or potential Agronomique (I.N.R.A.) (Rennes, Mons, La Miniè re, Dijon, and values. Additionally, to discover which factors or condi-Ondes) during 1991 and 1992. Two important variates, the reduction tions are responsible for yield reductions, it is necessary of kernel number and the reduction of thousand kernel weight, were to characterize the nutritional status of the crop and analyzed to characterize the environments during the formation of yield. The former described the time-period until flowering and the the environmental and biological constraints and relate latter the grain-filling period. In addition, factors that limit yield were these indicators to yield component reductions. These determined through indicators such as water deficits, the ratio between factors are numerous in winter wheat trials. Climatic nitrogen absorbed and kernel number, radiation, temperature, develconstraints include water deficits (Singh, 1981; Kobata opment of diseases (powdery mildew, strike rust, leaf rust, leaf and et al. , 1992; Debaeke et al., 1996), temperature (Wieglume blotch), and lodging. Our study resulted in providing critical gang and Cuellar, 1981; Hunt et al., 1991; Stone and values for grain yield, kernel number, and thousand kernel weight Nicolas, 1995a, b), and radiation (Demotes-Mainard et for the four probe genotypes. Then reductions of yield components al., 1996). In French cropping systems, biological concould be determined and analyzed. They provide useful information straints are associated with diseases. More than 20 disfor characterizing environments subjected to numerous yield-limiting eases of major significance have been reported on wheat factors. Our study also revealed that the biological variates (essentially susceptibility to powdery mildew and to lodging) affected yield more

Diagnosis of limiting factors of organic oilseed rape yield. A survey of farmers’ fields

“…The regional agronomic diagnosis methodology, already tried and tested on several problems in conventional agriculture, was here adapted to a study of variation in yield in organic systems, where more numerous limiting factors could be observed. A stepwise regression procedure has been used in previous studies on the yield or on the final yield components such as number of grains and protein content (Brancourt-Hulmel et al, 1999;David et al, 2005;Le Bail and Meynard, 2003). In our study, a range of possible limiting factors throughout the crop cycle led us to use a regression procedure for different periods, using the yield components during spring and biomass during autumn as dependent variables.…”

Associations among Twenty Years of International Bread Wheat Yield Evaluation Environments

“…The influence of temperature (Haji and Hunt, 1999), its effects on maturity date (Peterson and Pfeiffer, 1989; Abdalla et al, 1996) and inferences for location clustering have been noted previously. Others found that diseases rather than climatic variables influence site associations (Brancourt‐Hulmel et al, 1999). The observed relationship between irrigated locations and rainfed sites in the current study was influenced by the shuttle breeding method used by CIMMYT (Braun et al, 1996).…”

Nitrogen Remobilization during Grain Filling in Wheat: Genotypic and Environmental Effects

“…It is therefore unlikely that all genotypes were subjected to the same limiting factors or to the same intensity of limiting factor. We characterized each environment for the main yield‐limiting factors identified, with a diagnostic method and three probe genotypes, as described by Brancourt et al (1999). These three genotypes were chosen on the basis of their known response to several environmental factors and to cover the range of earliness of the 10 genotypes used in this study.…”

“…In each environment, the grain yields obtained were compared with potential yields for each probe genotype. Potential yields were determined as described by Brancourt et al (1999), using a bootstrap procedure: 1000 samples of 200 points were taken from a large body of available experimental data (382 data for Camp‐Rémy, 274 data for Récital, and 829 data for Soissons). Maximum yield was determined for each sample, and the mean and standard deviation of the maxima obtained for each sample were taken as the potential yield values (10.3 Mg ha −1 ± 0.5 for Camp‐Rémy, 10.1 Mg ha −1 ± 0.4 for Récital, and 10.5 Mg ha −1 ± 0.6 for Soissons).…”