GENETIC VARIABILITY OF BEAN SEED IN RESISTANCE TO HEAT TREATMENT
The principal aim of these preliminary trials was to show how far the seeds could stand heat treatment; hence dry heat was used for them, because it is much simpler to apply than the other two forms of heat treatment commonly used, hot water and aerated steam.
After the treatment, the seeds were put to germinate in the laboratory, following the I.S.T.A. methods.
The first results obtained indicate that the bean cannot stand temperatures over 80°C, and in any case at such levels the exposure to heat is bound to be too short, so that serious doubts arise as to the efficacy of the treatment from the point of view of disinfection. On the other hand, treatment for 6 hours at 60°C seems to have excellent prospects. It was found to do no serious harm either to the seeds during the germination stage, or to the subsequent development of the seedlings in natural growing conditions.
Differences were observed in the degree of resistance to the heat treatments of the two species of bean analysed: Phaseolus vulgaris cv. "Rampicante scarlatto di Cuneo" and P. multifloris cv. "Bianco di Spagna".
The former was found to be more resistant than the latter.