Ocena genotipova ječma na otpornost prema suši u fazi nalivanja zrna

Abstract

Nakon formiranja broja zrna po klasu u toku vegetativne faze, masa zrna zavisi od intenziteta i duţine nalivanja zrna. Međutim, u većini regiona u svetu u kojima se gaji ječam, pa i u Srbiji, česta je pojava suše i visokih temperatura tokom nalivanja zrna. Cilj ovog istraţivanja je bio da se identifikuju genotipovi dvoredog i šestoredog ječma koji mogu da postignu relativno visoke prinose u uslovima terminalne suše, kao i utvrđivanje korelacionih veza između ispitivanih osobina radi utvrđivanja kriterijuma za indirektnu selekciju na otpornost na sušu u periodu nakon cvetanja. Genetički materijal korišćen u ovom istraţivanju činilo je 15 genotipova dvoredog i 10 genotipova šestoredog ječma. Ogled je postavljen po potpuno slučajnom blok sistemu, na lokalitetima Zemun Polje i Školsko dobro, u dva ponavljanja, dva tretmana i dve godine (2010/2011 i 2011/2012). Jedan tretman je bio kontrolni, dok je u drugom izvršena mehanička defolijacija listova sedmog dana nakon cvetanja svakog genotipa. Na taj način su putem inhibicije tekuće fotosinteze simulirani uslovi suše u periodu nalivanja zrna. Uzorci klasova su uzimani na svakih pet dana, od momenta defolijacije do pune zrelosti. Defolijacija je uticala da se kod većine osobina srednje vrednosti značajno razlikuju (P<0.05) u odnosu na kontrolu, a do najvećeg smanjenja je došlo kod ukupnog prinosa zrna za 33%, ukupne biomase za 31%, prinosa po klasu za 14% i intenziteta nalivanja za 12%. Analiza varijanse je pokazala da je u uslovima stresa, u proseku za sve osobine, uticaj faktora genotip na variranje osobina nešto veći u odnosu na kontrolne uslove (36,5% prema 34,2%), dok je uticaj faktora sredine veći u kontrolnim u odnosu na uslove defolijacije (41,4% prema 34%)...

After the kernel number per spike has been formed during the vegetative stage, grain weight depends on the rate and duration of grain filling. However, drought and high temperatures during the grain filling stage frequently occurs in the majority og barley growing regions world wide, and Serbia too. The aim of this study was to identify two- and six- rowed barley genotypes with capacity to have comparatively high yields in terminal drought conditions, and to determine correlations among investigated traits in order to define criteria for indirect selection for resistance to drought in the period after flowering. The genetic material used in this study encompassed 15 and 10 genotypes of two-rowed and six-rowed barley, respectively. Genotypes were grown in a randomised complete block design trial with two replications, two treatments at two locations (Zemun Polje and Školsko dobro) in the period 2010-2011 and again in 2011-2012. One treatment was control, while in the other treatment mechanical defoliation was performed, 7 days after flowering of each genotype. Through the inhibition of current photosynthesis (as result of defoliation), the treatment simulated drought conditions during grain filling. Spike sampling was initiated at the moment of defoliation, and continued at 5 day interval until full maturity. Defoliation resulted in significant (P <0.05) difference in mean values in the majority of traits in comparison with the control, and the largest reduction was recorded in the total grain yield (33%), the total biomass (31%), the yield per spike (14%) and the grain filling rate (12%). The analysis of variance showed that under conditions of stress, on average for all traits, effects of genotypes on variation in traits were somewhat higher than in the control (36.5% vs. 34.2%)...