Contribution of pre-anthesis assimilates to grain yield and nitrogen content in spring barley

Abstract

Growing kernel of barley (Hordeum vulgare L) can be supplied with carbohydrate and nitrogen (N) from current assimilation or from translocation of pre-anthesis accumulated reserves, which are stored in the vegetative plant parts. This study was conducted to assess the contribution of pre-anthesis accumulated dry matter (DM) and N to grain yield and N content in spring barley. Eight spring barley cultivars were grown on a non-calcareous chernozem soil in three growing seasons (1995-1997) at Novi Sad (45°20' N, 15°51' E, 86 m asl) at two N levels - low and high N level. Pre-anthesis DM contributed to total DM at anthesis 44, 33, and 31% in 1995 1996, and 1997, respectively. DM translocation occurred only in favorable growing conditions. The cultivars did not differ in vegetative DM at anthesis and maturity and yield. N accumulated at pre-anthesis represented 92, 68, and 51% at the low N level and 138, 76, and 54% of total N at maturity at the high N level in 1995, 1996, and 1997, respectively. Depending on the year and N level, translocated N across cultivars represented 34-171% of grain N. Nitrogen losses occurred when anthesis N exceeded 150 kg.ha-1. Selection of genotypes with a higher ability of pre-anthesis reserve utilization or genotypes with efficient post-anthesis DM and N accumulation may be two possible solutions in spring barley breeding for semiarid growing conditions.

Ugljeni hidrati i azot (N) neophodni za nalivanje zrna ječma (Hordeum vulgare L) mogu voditi poreklo od tekuće fotosinteze ili od translociranih, pre cvetanja akumuliranih rezervnih materija u vegetativnim delovima biljke. U radu je prikazan značaj suve materije (SM) i N akumuliranog do cvetanja na prinos i sadržaj N u zrnu u osam sorti jarog ječma tokom tri godine ispitivanja (1995-1997) pri gajenju na dva nivoa ishrane azotom - niski N i visoki N. Akumulirana masa SM do cvetanja predstavljala je 44%, 33% i 31% ukupne nadzemne SM u zrenju u 1995, 1996. i 1997. godini. Translokacija SM u zrno odvijala se samo u povoljnim ekološkim uslovima proizvodnje. Ispitivane sorte nisu se razlikovale u masi akumulirane SM u cvetanju, zrenju i prinosu zrna. Od ukupnog N utvrđenog u zrenju do cvetanja je akumulirano 92% kod niskog i 138% kod visokog nivoa N u 1995. godini, 68% kod niskog i 75% kod visokog nivoa N u 1996. godini i 51% kod niskog i 54% kod visokog nivoa N u 1997. godini. Zavisno od godine i nivoa N, translocirani N je predstavljao 34-171% N utvrđenog u zrnu kod žetve. Gubitak N iz biljaka se javio u uslovima kada je u fazi cvetanja ukupni N u nadzemnom delu useva iznosio preko 150kg ha-1. Selekcija genotipova veće sposobnosti iskorišćavanja do cvetanja akumulirane SM i N ili genotipova sa efikasnijom akumulacijom SM i N tokom nalivanja zrna predstavljaju dva načina oplemenjivanja jarog ječma za semiaridne uslove proizvodnje. Gajenje ovakvih genotipova može doprineti smanjenju upotrebe N u proizvodnji, očuvanju životne sredine i proizvodnji zdravstveno bezbedne hrane.