Importance of spikelet formation phase in the yield biology of winter barley

Abstract

Plants evolve through strictly defined stages of development, which can be identified by changes in plant phenotype or by changes in the morphology of apical meristem. Differentiation of apical meristem passes through phases that proceed in a precise chronological order. This paper analyzes the significance of the length of the period of spikelet primordia formation i.e. the double ridge (DR) phase, and its genotypic and phenotypic correlation with the other growth phases and yield components. In the course of five growing seasons (2002-03 to 2006-07) we studied the development of apical meristem in three two-rowed winter barley cultivars - Novi Sad 525 Sonate and Monaco. DR stage was shortest in the seasons with favorable weather conditions during that stage. It was longest when conditions were unfavorable, especially when temperatures were high. The shortest DR stage was found in the early cultivar Novosadski 525, the longest in the medium early cultivar Sonate. The cultivars had similar genotypic and phenotypic correlations between the length of DR stage on one side and the duration of the other development stages and yield components on the other side. DR period length was positively correlated with the duration of the formation of leaf primordia and negatively correlated with the other development stages i.e. grain filling period, numbers of leaves and spikes and harvest index. The obtained results may find practical application in winter barley breeding. Further more detailed study involving a number of cultivars is required in order to confirm the above results.

Biljke prolaze kroz tačno definisane faze razvića koje mogu biti predstavljene na osnovu promena koje se dešavaju na fenotipu biljke ili na osnovu promena u morfologiji apikalnog meristema. Diferencijacija apikalnog meristema odvija se kroz faze koje se nalaze u određenom hronološkom redosledu. U radu je analiziran značaj dužine formiranja primordija klasića faza dvostrukog grebena (DR) i njene genotipske i fenotipske povezanosti sa ostalim fazama razvića i komponentama prinosa. Tokom pet sezona (od 2002-2003. do 2006-2007) proučavano je razviće apikalnog meristema kod tri sorte ozimog dvoredog ječma Novosadski 525, Sonate i Monaco. DR faza je bila najkraća u sezonama kada su vladali povoljni vremenski uslovi tokom odvijanja ove faze, a najduža kada su uslovi bili nepovoljni, pre svega visoke temperature. Najkraći DR period imala je ranozrela sorta Novosadski 525, a najduži srednje rana sorta Sonate. Utvrđene su slične genotipske i fenotipske korelacije između dužine DR i dužine trajanja ostalih faza razvića i komponenti prinosa. Dužina DR perioda bila je u pozitivnoj korelaciji sa dužinom perioda formiranja primordija listova, a u negativnoj korelaciji sa ostalim fazama razvića, periodom nalivanja zrna, brojem listova i klasova i žetvenim indeksom. Formiranje primordija listova i klasića kao i razviće cvetova i klasića nalazi se pod najvećom kontrolom genotipa, gde je učešće varijanse sorte preko 80% i godine do 10%. Dobijeni rezultati mogu imati praktičan značaj u oplemenjivanju ozimog dvoredog ječma. Za potvrđivanje ovih rezultata neophodna su detaljnija istraživanja sa većim brojem sorti.