Genetic analysis of photoinhibition in barley.

摘要

Winter cereals are acclimated during wintering, and thereafter their freezing resistance is increased. In order to analyse inheritance and heritabilities for photoinhibition of photosynthesis by high light intensity under low temperature, and to evaluate the relationship between low temperature-induced photoinhibition and winter survival, 4 parental half diallel crosses were used with the barley cultivars Sacheon 6, Oweolbori, Dongbori 1 and Reno as parents. The detached leaves of 7-8 cm long fromplants grown for 35 and 55 days were placed on wet filter paper and placed in trays at 5℃ cold room with 1200μmol m-2s-1 PPFD. Chlorophyll fluorescence was measured with a chlorophyll fluorescence system after dark adaptation for 30 min. The Fv/Fm of 35-day old plants was reduced from 0.714 in the control leaves to 0.409 and 0.368 following photoinhibitory treatment of 6 h and 8 h and the coefficients of variation were increased from 0.8% to 22.2-22.3%. The Fv/Fm of 55-day old plants was reduced from0.775 in the control leaves to 0.485 and 0.439 following photoinhibitory treatment of 10 h and 12 h, respectively. According to half diallel cross analysis, Reno and Dongbori 1 (highly resistant to photoinhibition) was dominant, but Oweolbori (susceptible to photoinhibition) was recessive, and photoinhibition showed partial dominance with highly additive gene action. Dongbori 1 showed the greatest GCA effects for photoinhibition, and GCA/SCA ratios (8.7-22.3 times) indicated that the additive variance for the character was more important. Winter survival in barley crosses was positively correlated with resistance to photoinhibition and significantly fitted by linear regression (R2=0.751**-0.779**). The chlorophyll fluorescence measured by Fv/Fm has been found to be highly inheritable and very useful in evaluating relative levels of freezing resistance in barley.