An index to quantify seed moisture loss rate in relationship with seed desiccation tolerance in common vetch

作者：Samarah N H^*; Mullen R E; Alqudah A M

来源：Seed Science and Technology, 2009, 37(2): 413-422.

DOI：10.15258/sst.2009.37.2.14

Common vetch seeds are desiccation intolerant when seeds are harvested at immature stages of development and extracted from pods before drying. Drying the immature seeds in intact pods improved desiccation tolerance in association with slow drying rate; however, an index to quantify the rate of seed moisture loss has not been studied. Therefore, the objective of this experiment was to develop an index to quantify the rate of moisture loss of common vetch seeds subjected to four drying methods in association with their desiccation tolerance. During the reproductive growth stage, seeds were harvested at four maturity stages: 1) beginning seed fill (BS), 2) fullsize seeds (FS), 3) yellow pods (Y), and 4) brown pods (B). Seeds were dried at 20 degrees C +/- 2 by four methods: 1) dried in intact pods, 2) extracted from pods and dried under ambient conditions (Ambient), 3) extracted from pods and rapidly dried under low relative humidity for 6 days (Low RH), 4) extracted front pods and slowly dried over a gradually declining relative humidity for 6 days (Gradually Declining RH). Seed moisture content was measured during the drying period to develop a Seed Moisture Loss Rate index (SMLR). Seed desiccation tolerance was estimated by Measuring the percentage of normal seedlings in a standard germination test for air-dried seeds. Drying the seeds in intact pods improved the desiccation tolerance at the BS, FS, and Y stages, while drying the seeds under a gradually declining RH improved the desiccation tolerance at FS stage as compared with those dried under ambient or low RH. This improvement in seed desiccation tolerance was associated with drying rate as estimated by SMLR index. A dramatic reduction in seed desiccation tolerance was observed when SMLR index increased above 19. These data emphasized that desiccation tolerance was,in independent mechanism in seeds which can be acquired in seeds harvested as early as beginning seed fill. Seed moisture loss rate index can be a very useful tool to assess seed desiccation tolerance of different crop species in relationship with their drying rate under various field conditions.

• 出版日期2009