Genotypic response of South African wheat cultivars to photoperiod, vernalization and adaptation

[摘要] English: The aim of this study was to determine the response of South Africanbread wheat cultivars to vernalisation and photoperiod and to group thegenotypes accordingly. In addition to this the way in which the responseof genotypes to vernalisation and photoperiod attributes to yield stabilitywas also investigated.Thirty South African wheat cultivars were included in two separate trials toevaluate their response to vernalisation and photoperiod treatments. Thewheat cultivars were selected to represent cultivars planted in all the mainwheat production regions of South Africa. The range of genotypesincluded cultivars with no vernalisation requirement to cultivars with verystrong vernalisation requirements.The vernalisation trial consisted of 30 South African wheat cultivarssubjected to eight vernalisation treatments, ranging from zero to sevenweeks vernalisation. Each treatment had eight replicates on which daysto heading, flowering and physiological maturity were observed. Clusteranalysis was done to group the cultivars into similarity groups. Fourgroups were identified: 1) True winter wheats encompassing: Molen,- -SST936, SST966, SST399, and 2) Winter wheats that included Betta-ON,Caledon, Elands, Hugenoot, PAN3235, SST367, and SST983, 3)Intermediate wheats consisting of Gariep, Limpopo, PAN3211, PAN3349,PAN3377, SST124, SST363, and Tugela-ON, and 4) Spring wheatsincluding Baviaans, Inia, Kariega, Marico, Palmiet, Steenbras, SST57,SST65, SST88, SST822, and SST876.The photoperiod trial involved 30 South African wheat cultivars subjectedto three photoperiod treatments (10, 14, and 18 hours day light). Tenreplicates were included for each treatment. Days to heading, floweringand physiological maturity were recorded for all cultivars. Clusteranalysis was performed and four discreet response classes identified.The classes were denominated as Group 1, Group 2, Group 3, and Group4. Group 1 consisted of only one cultivar SST399. Group 2 included allthe following true winter, winter, and intermediate wheat cultivars: Molen,Betta-DN, Caledon, Elands, Hugenoot, PAN3235, SST367, Limpopo,Gariep, PAN3211, PAN3349, PAN3377, SST124, SST363, and Tugela-ON. The only cultivars in Group 3 are the hybrid wheats: SST936,SST966, and SST983. Group 4 included all the spring wheat cultivars:Baviaans, Inia, Kariega, Marico, Palmiet, Steenbras, SST57, SST65,SST88, SST822, and SST876.Data obtained from the vernalisation and photoperiod trials were used inconjunctiqn with data from cultivar evaluation trials to determine therelationship between the response to vernalisation, photoperiod and yieldstability. Yield data from the three main wheat production areas: FreeState (14 sites), Irrigation areas (13 sites), and the Western Cape (12sites) were used to calculate yield stability. Correlations betweenresponse to vernalisation, photoperiodic and yield stability were found tobe weak, although stronger correlations were observed betweenvernalisation response and yield stability in the Western Free State,Central Free State, and warmer irrigation areas.The data from this study suggest that wheat should be classes as true·winter, winter, intermediate, and spring wheats, and that trial layoutsshould be planned according to these classes.

[发布机构] University of the Free State