PHENOLOGY OF Calotropis procera (Ait.) W.T. Aiton ACCESSIONS BASED ON MORPHOPHYSIOLOGICAL CHARACTERISTICS

ABSTRACT The objective of this work was to evaluate the phenology of Calotropis procera accessions based on morphophysiological characteristics. Seeds of 70 C. procera accessions were collected between October 2015 and January 2016 in areas where the species naturally occurs in Northeastern Brazil. These accessions make up the current germplasm collection of the National Institute of the Semi-arid (INSA). The experiment was conducted in a greenhouse at INSA, in Campina Grande - PB, from January to September in 2016. The plants were cultivated in plastic pots filled with soil. Fertilization was conducted according to soil analysis recommendations and plants were irrigated at a 3-day interval. Morphophysiological characteristics were recorded 30 days after sowing (DAS) and 30-day intercalated evaluations were conducted up to 240 DAS. In addition, physiological indexes were estimated and leaf fall, flowering, and fruiting were evaluated at 120 DAS. Mean of each characteristic was obtained using the adjustment and the selection of regression models to explain the growth of C. procera based on the coefficient of determination. The vegetative stage of C. procera occurs during the 240 DAS, with continuous fall and production of leaves, while the reproductive stage begins at 153 DAS, continuing until 222 DAS, depending on the accession, making emission of inflorescences constant on plants after the beginning of flowering. The physiological indexes are efficient to estimate the growth of C. procera accessions.

摘要 本研究旨在基于形态生理特性，评价牛角瓜（Calotropis procera）种质的物候期。2015年10月至2016年1月期间，在巴西东北部该物种自然分布区域，采集了70份牛角瓜种质的种子。这些种质构成了半干旱地区国家研究所（National Institute of the Semi-arid, INSA）的现有种质资源库。本试验于2016年1月至9月在巴西帕拉伊巴州坎皮纳格兰德的INSA温室中开展。供试植株种植于装填土壤的塑料盆中，施肥依据土壤分析结果制定的方案进行，植株每3天灌溉一次。于播种后30天（Days After Sowing, DAS）记录形态生理特性，并每隔30天开展一次跟踪评价，直至播种后240天。此外，于播种后120天测定生理指标，并评价落叶、开花与坐果情况。基于决定系数，通过回归模型的拟合与筛选，推导得到各性状的平均值，以阐释牛角瓜的生长过程。牛角瓜的营养生长期贯穿播种后240天内，期间叶片持续脱落与新生；而生殖生长期始于播种后153天，持续至播种后222天，具体时长因种质而异，开花启动后植株的花序萌发始终保持稳定。生理指标可有效评价牛角瓜种质的生长状况。