St. Otubo et al., GENETIC-CONTROL OF LOW-TEMPERATURE TOLERANCE IN GERMINATION OF THE COMMON BEAN (PHASEOLUS-VULGARIS L), Euphytica, 89(3), 1996, pp. 313-317
Cultivars tolerant to low temperature during the germination and emerg
ence stages and carriers of the grain quality standards demanded by co
nsumers are needed to increase the success of irrigated common bean in
Southern Minas Gerais State. To study the genetic mechanisms controll
ing these traits and assess the possibility of generating the desirabl
e materials, a diallel cross involving ten cultivars including introdu
ctions and pure lines from the breeding program of ESAL was carried ou
t. Speed of germination of the F-2 generation from the crosses was ass
essed under laboratory conditions at 12 degrees C. The diallel analysi
s was carried out using Griffing's method IV (1956) and predictions of
the cross potential were made by the methodology developed by Jinks &
Pooni (1986). The results indicated that the parents differed in germ
ination speed at low temperatures with 'Small White', 'A-488' and 'Rio
Vermelho' being the most tolerant and 'Carioca', 'ESAL 609' and 'ESAL
, 591' the most sensitive. No effect of the reciprocal crosses was obs
erved either for germination percentage or germination speed. The pare
nts 'A-488', 'Small White' and 'Rio Vermelho' showed the greatest gene
ral combining ability. Additive genetic effects predominated for both
traits. Our results suggest that cold tolerance can be bred successful
ly into commercially acceptable cultivars.