Multivariate analysis in the morpho-yield evaluation of forage cactus intercropped with sorghum

ABSTRACT Understanding the effect of the cropping system on the morpho-yield relationship of plants is crucial for success in the agricultural activity, mainly in arid and semi-arid regions, where there are major challenges for food production. In this study, the objective was to apply multivariate statistics in the morpho-yield evaluation of forage cactus clones in cropping systems as sole crop and intercropped with sorghum cultivars. The experiment was conducted in Serra Talhada, PE, Brazil, between March 18, 2017 and June 16, 2018. The design adopted was in randomized blocks with 12 treatments composed of three forage cactus clones in sole-crop system (IPA Sertânia, Miúda and Orelha de Elefante Mexicana) and nine forage cactus-sorghum intercropping systems with the cultivars 467, SF11 and 2502. Morphometric and phytomass measurements of forage cactus clones were performed throughout the cycle. The relationship between the morpho-yield traits of the clones was evaluated by means of principal component analysis. Cladode width, length, perimeter, and area are morphometric variables that determine phytomass accumulation in clones. The cropping systems did not influence the association of morpho-yield traits, but it depends on the genus of forage cactus. Negative correlations between cladode dimensions and phytomass of the clones of the genus Nopalea explained their lower phytomass accumulations. Principal components analysis makes it possible to elucidate associations between morpho-yield variables of forage cactus.

摘要 明晰种植制度对作物形态-产量关系的影响对农业生产的成功开展至关重要，这一点在粮食生产面临诸多严峻挑战的干旱半干旱地区尤为突出。本研究旨在将多元统计方法应用于单作及与高粱品种间作的饲用仙人掌无性系的形态-产量评价中。本试验于2017年3月18日至2018年6月16日在巴西PE州塔尔哈达（Serra Talhada）开展，采用随机区组设计，共设置12个处理：3个单作饲用仙人掌无性系处理（IPA Sertânia、Miúda以及墨西哥象耳仙人掌(Orelha de Elefante Mexicana)），以及9个饲用仙人掌与高粱品种间作的处理，所用高粱品种为467、SF11和2502。在整个生育周期内，对饲用仙人掌无性系开展形态计量学与植物生物量测定。采用主成分分析(Principal Component Analysis)方法，对无性系的形态-产量性状间的关联进行评价。茎片的宽度、长度、周长及面积是决定无性系植物生物量积累的形态计量学变量。种植制度并未对形态-产量性状的关联产生影响，但该关联取决于饲用仙人掌的属类。似梨仙人掌属(Nopalea)无性系的茎片尺寸与生物量间呈负相关，这解释了该属无性系较低的生物量积累水平。主成分分析可有效阐明饲用仙人掌形态-产量变量间的关联关系。