Odnos fenoloških faza i prinosa zrna kod ozimog ječma u semiaridnim uslovima

Each yield component of barley is determined by developmental events during specific phenological phases. The number of spikes per unit area is established from tillering to jointing. The number of kernels per spike is established from jointing, i.e., it starts from double-ridge of apical meristem development and sets shortly after anthesis. Duration and rate of grain filling (GF) determines kernel weight. The objectives of this study were to examine the variation and relationships among phenology and yield components. Twenty-four winter barley cultivars were used in this investigation. The stage of leaf development of the main culm was referenced to the Haun scale. All phenological measurements were assessed using growing degree days (GDD) with a base temperature of 0˚C. The relationship between kernel weight and GDD accumulated from anthesis for each plot was determined by fitting the quadratic polynomial. The duration from planting to flag leaf elongation stage was 1223 GDD across two-rowed varieties and 1304 GDD across six-rowed varieties. The variety NS 519 had the shortest GF period (648 GDD), the variety Marinka the longest (940 GDD). GF rate was mainly determined by genotype (44.3% of total variation) and GxY interaction (31.1% of total variation). GF rate across two-rowed varieties was rather higher (7.251 mg 100 GDD-1) than across six-rowed varieties (6.395 mg 100 GDD-1). The duration of the vegetative and generative phases should be balanced, since neither too early nor too late a flowering will bring maximum yields. Our results show that the pre-heading period varied more than the GF period in the tested varieties. Selection for shorter vegetative period and longer GF period is recommended in the development of varieties for semiarid conditions of growing.Komponente prinosa ječma formiraju se u određenim fenološkim fazama: broj klasova tokom bokorenja, broj zrna po klasu tokom vlatanja pa do završetka cvetanja, a masa zrna od formiranja zrna do fiziološke zrelosti. Cilj ovog istraživanja bio je da se utvrdi odnos između fenoloških faza i komponenti prinosa kod 24 sorte ozimog ječma. Faze razvoja lista glavnog stable određene su na osnovu skale po Haun-u. Kao vremenska skala kod fenoloških opažanja korišćena je suma temperatura većih od 0°C (GDD). Odnos između mase zrna i sume temperature u toku perioda rasta određen je pomoću kvadratne jednačine. Prosečna suma aktivnih temperatura od nicanja do pojave lista zastavičara bila je 1223 GDD kod dvoredih sorti i 1304 GDD kod šestoredih sorti ječma. Sorta NS 519 imala je najkraći (648 GDD) a sorta Marinka najduži period nalivanja zrna (940 GDD). Period nalivanja zrna uglavnom je zavisio od sorte (44,3% od ukupne varijanse) i interakcije GxY (31,1% od ukupne varijanse). Intenzitet nalivanje zrna kod dvoredih sorti (7.251 mg 100 GDD-1) bio je značajno veći nego kod šestoredih sorti (6,395 mg 100 GDD-1). Kako bi se ostvario maksimalan prinos i kvalitet, trajanje vegetativne faze, tokom koje se formira broj klasova i zrna, i generativne faze, tokom koje se formira veličina i masa zrna, treba da bude uravnotežen. Naši rezultati su pokazali da kod ječma u semiaridnim uslovima dužina perioda do klasanja varira više nego dužina perioda nalivanja zrna. Selekcija sorti sa kraćim vegetativnim periodom i dužim periodom nalivanja zrna preporučuje se prilikom izbora sorti namenjenih za gajenje u semiaridnim uslovima