The effect of cold temperature stress on the viability of rye ( Secale cereale L.) microspores

Abstract

Rye has been generally considered to be recalcitrant to the androgenesis induction in vitro. The haploids of Secale cereale are not easily obtainable and the isolated microspore technique application is difficult, thus is performed occasionally, and in a limited number of strains and cultivars. The aim of the conducted experiment was to assess the frequency of mechanical damage in microspores after their isolation in the mortar, and the effect of the pretreatment of spikes at 4EC on microspore viability and the course of the culture. The analyses in the isolated microspore culture were conducted on 30 genotypes of rye from two breeding programs and differing in their origin. Spikes with microspores in the unicellular stage were cut and exposed to a temperature of 4EC for a period of 2 to 42 days. Microspore observations were conducted immediately after the microspore isolation in order to assess the viability and percentage of the damaged ones. In order to study the mitotic divisions first, cultures of rye microspores were examined after 3 days. The highest microspore viability after isolation was observed for strain 1283C – 91.9% and inbred line S1152/10 – 91.8%, while it was the lowest for F 1 hybrid S02779/10 – 79.8% and strain 1252E – 84%, respectively. It was found that to maintain high (microspore – to mozna opuscic) viability, microspores must be isolated after low temperature stress (+4EC) applied for up to 7 days of culture. A considerable extension of the duration of low temperature (36-42 days) resulted in a reduction of the microspore isolation efficiency in rye (a lower number of microspores in the obtained suspension) and a slight reduction of microspore viability.