Base-temperature, plastochron and chia (Salvia hispanica L. - Lamiaceae) yield for different sowing times

ABSTRACT Chia is a plant whose seeds are used in cooking and is a natural source of omega-3 fatty acids, fiber and protein, as well as other important nutritional components such as antioxidants. The objective of this work was to estimate the base temperature, plastochron and chia seed yield for different sowing times in Cruz Alta, Rio Grande do Sul, Brazil. The experimental design was completely randomized and the treatments consisted of different sowing times (September, October and November). For the determination of the base temperature for node emission in the main stem of the plants, the method of least mean square error of linear regression between the number of nodes and the accumulated thermal sum was used. Regarding estimation of the plastochron at each sowing time, a simple linear regression was obtained between the number of nodes in the main stem and the accumulated thermal sum. Seed yield was measured at harvest. Sowing in times with air temperature below 19 ºC should be avoided so that the development of plants is not impaired. Plastochron ranges from 28.01 ºC to 32.26 ºC day for successive node emission in the main stem of chia plants and September sowing promotes higher seed yield.

摘要：奇亚是一种种子可供烹饪使用的植物，其天然富含Omega-3脂肪酸、膳食纤维、蛋白质及抗氧化剂等多种重要营养组分。本研究旨在针对巴西南里奥格兰德州克鲁扎阿尔塔地区的不同播期，估算奇亚的基部温度、出叶间隔期（plastochron）与奇亚籽产量。试验采用完全随机设计，设置9月、10月、11月三个播期处理。为测定植株主茎节间发生的基部温度，本研究采用节点数与累积积温间的线性回归最小均方误差法开展计算。针对各播期下的出叶间隔期估算，本研究通过主茎节点数与累积积温间的简单线性回归模型完成拟合。于收获期测定奇亚籽产量。应避免在气温低于19℃的时段播种，以免植株生长发育受阻。奇亚植株主茎连续节间发生的出叶间隔期为28.01~32.26℃·日，且9月播种可获得更高的奇亚籽产量。