Breeding progress in grain filling and grain yield components of six-rowed winter barley

The objectives of this study were to quantify the grain yield breeding progress and identify the changes in numerical yield components and grain filling traits of six-rowed winter barley (Hordeum vulgare L.) cultivars under different nitrogen (N) fertilization treatments: 0 kg ha(-1) N (0N, control) and 100 kg ha(-1) N (100N). Field trials were conducted during two (2015-2016 and 2016-2017) growing seasons in a southern Pannonian location, Novi Sad, Serbia with fifteen six-rowed winter barley cultivars. The rate of genetic gain in grain yield was 0.055 t ha(-1) yr(-1) at 0N, while at 100N genetic gain was 0.061 t ha(-1) yr(-1), indicating that modern winter barley cultivars use the applied N fertilizer more efficiently than older cultivars. Grain yield progress was mainly associated with increased grain number per unit area, grain number per spike, grain weight and harvest index. A positive linear correlation was determined between fruiting efficiency and the year of cultivar release, while changes in spike dry weight at anthesis as influenced by the year of cultivar release were not significant. Breeding progress in grain weight was more related with grain filling and maximum grain filling rate, while grain weight association with grain filling duration was less pronounced. Therefore, further grain yield improvement in six-rowed winter barley should be achieved by simultaneous increase in grain weight and grain number per spike, while maintaining high values of harvest index

Changes in leaf appearance and developmental phases associated with breeding progress in six-rowed barley in the Pannonian Plain

The aim of this study was to analyze traits of leaf appearance and phenological development related to grain yield gain in winter barley cultivars released over the past 50 years. Field trials with 15 six-rowed winter barley cultivars were conducted during two growing seasons. The main leaf appearance and developmental traits were studied. The duration of the emergence-anthesis and emergence-physiological maturity phases decreased by 2.35 and 2.16 GDD yr(1), respectively. The duration of the stem elongation-anthesis phase was 10% longer in modern cultivars. The results showed no clear trend of improvement in final leaf number and phyllochron. The duration of the stem elongation-anthesis phase was positively related with grain number and yield. Constant improvements in grain number and grain weight by fine manipulation of the crop developmental phases could represent an essential strategy for further increases in barley grain yield potential

Changes in stay-green and nitrogen use efficiency traits in historical set of winter barley cultivars

The objective of this study was to compare grain yield, nitrogen use efficiency (NUE) and stay-green traits in winter barley under low and high nitrogen (N) fertilization treatments. Field trials were conducted during two growing seasons in a southern Pannonian location (Novi Sad, Serbia) with fifteen six-rowed barley cultivars released between 1972 and 2013. The rate of genetic gain in grain yield was higher under high N level, indicating that modern barley cultivars use the applied N fertilizer more efficiently than older cultivars. The improvement in NUE and N uptake efficiency were positively related with year of cultivar release under both fertilization levels, while association between N utilization efficiency and year of cultivar release was significant at high N fertilization. Modern cultivars had higher normalized difference vegetation index (NDVI) values at the anthesis, start and mid senescence. Moreover, time to mid senescence was prolonged in modern cultivars, indicating slower N remobilization during early grain filling period. Values of NDVI at different senescence stages were more related to N uptake efficiency, while timing of senescence stages were in association with N utilization. Close association between NDVI values at different senescence stages and N uptake indicate that application of NDVI sensors could be used for identification of cultivars with improved N productivity