Germination and viability coefficients of Faba Bean (Vicia faba) seed under different storage conditions

Pulses are among the best sources of plant protein and important components of crop rotation, which in recent years, have been considered one of the major options for plant research. Seed storage is one of the important traits in legume breeding. Storage temperature, seed moisture content, and storage duration are the most important factors affecting seed quality during storage. Inappropriate storage conditions lead to deterioration and reduction of seed quality during storage, which is severely affected by the environmental conditions of storage.

This research was conducted at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2014 as a three-way factorial based on the completely randomized design with 5 replications of 20 seeds. Seeds with moisture content at 5 levels (6, 10, 14, 18, and 22%) and storage temperature at 4 levels (15, 25, 35 and 45 °C) were stored for 9 months (0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 days). After sampling at the end of each month, a standard seed germination test was done using the pleated paper method in a germinator at 25 °C for 10 days. Also, an electrical conductivity test of the electrolytes leaked from the seeds incubated for 24h in water at 20 ˚C was done with 4 replicates. Some germination attributes and electrical conductivity of the electrolytes leaked from the seeds were measured according to standard methods.

According to the results, interaction effects of storage temperature, seed moisture content, and storage duration on germination indices and electrical conductivity of bean seeds were significant (P<0.1). The germination trend during storage at 15 °C and seed moisture content of 6% decreased from 94% to 81% after 270 days of storage, so that germination decreased to 35% under similar moisture content after 270 days of storage as temperature increased from 15 to 45 °C. As the storage time passed, electrical conductivity increased and this increase was more pronounced at higher temperatures. Viability constants were calculated 9 months after storage using the seed viability equation, in which KE, CH, CW, and CQ were calculated -5.39697, 0.03201, 2.13041, and 0.000017, respectively.

The results showed that the electrical conductivity of the leaked material increased with increasing storage temperature and seed moisture content, which led to lower viability of seeds. At 15 °C and 6% seed moisture content provided better conditions for seed survival during the 9-month storage time compared with all other temperatures and moistures and had the lowest rate of deterioration. The results showed that with increasing seed temperature and moisture so that they had to lowest electrical conductivity of the leaked material from seeds and deterioration rate.