Pattern analysis of international sorghum multi-environment trials for grain-yield adaptation

 Pattern analysis, which consists of joint and complementary use of classification and ordination techniques, was applied to grain-yield data of 12 sorghum genotypes in 25 environments to identify the grouping of genotypes and environments. The 12 genotypes represented a wide geographical origin, different genetic diversity, and three photoperiod-sensitive classes. The 25 environments represented a super population of widely different environments covering latitudes from 20°S to 45°N. The knowledge of environmental and genotype grouping helped reveal several patterns of genotype×environment (GE) interaction. The existence of two mega-environments – African and Asian – was indicated. Within these mega-environments, several subgroups were further discernible. The Asian-type subgroups of environments tended to be closer to one another, suggesting that they discriminated genotypes similarly. By contrast, the African-type sub-groups of environments were more divergent. Differential genotype adaptation patterns existed in the two mega-environments. The repeatability of the GE patterns seen in this multi-environmental trial, however, needs to be established over time. Received: 4 April 1997 / Accepted: 6 October 1997     

Pattern formation in single cells

Single-cell patterning begins with an asymmetric cue that orients the axis of polarity. Despite great diversity in the types of cues, common mechanisms appear to mediate the polarizing response. Rho-family GTPases initially process and reinforce polarity cues by remodelling cortical actin, and these local asymmetries are subsequently propagated to the microtubules, membrane and secretory pathway to generate the final pattern. Homologues of the yeast polarity genes fulfil similar functions in higher eukaryotes, revealing a fundamental conservation in how polarity arises. Unlike yeast, however, more complex eukaryotic cells can manifest multiple axes of polarity, suggesting that additional mechanisms have evolved to generate more elaborate patterns.