Influence of tillage and residue management practices on productivity, sustainability, and soil biological properties of rice-barley cropping systems in indo-gangetic plain of India.

Introduction: Conservation agriculture is a sustainable system of farming that safeguard and conserves natural resources besides enhancing crop production. The biological properties of soil are the most sensitive indicator to assess the short term impact of management practices such as tillage and residue incorporation. Methods: Nine treatments of tillage and residue management practices [Reduced till direct seeded rice-zero till barley (RTDSR-ZTB); RTDSR-ZTB-green gram residue (Gg); Zero till direct seeded rice-zero till barley-zero till green gram (ZTDSR-ZTB-ZTGg); RTDSR-ZTB + rice residue at 4 t ha 1 (RTDSR-ZTBRR4); RTDSR-ZTBRR6; un-puddled transplanted rice (UPTR)-ZTB-Gg; UPTR-ZTBRR4; UPTR-ZTBRR6, and puddled transplanted rice (PTR)-RTB] executed under fixed plot for five years on crop productivity and soil biological properties under rice-barley production system. Results: The shifting in either RTDSR or ZTDSR resulted in yield penalty in rice compared to PTR. The PTR recorded highest pooled grain yield of 3.61 ha-1. The rice grain yield reduced about 10.6% under DSR as compared to PTR. The ZTB along with residue treatments exhibited significantly higher grain yield over ZTB, and the RTDSR-ZTBRR6 registered highest pooled grain yield of barley. The system productivity (12.45 t ha-1) and sustainable yield index (0.87) were highest under UPTR-ZTBRR6. Biological parameters including microbial biomass carbon, soil respiration, microbial enzymes (Alkaline phosphatase, nitrate reductase and peroxidase), fluorescein diacetate hydrolysis, ergosterol, glomalin related soil proteins, microbial population (bacteria, fungi and actinobacteria) were found to be significantly (p < 0.05) effected by different nutrient management practices. Based on the PCA analysis, Fluorescein diacetate hydrolysis, microbial biomass carbon, soil respiration, nitrate reductase and fungi population were the important soil biological parameters indicating soil quality and productivity in present experiment. The results concluded that UPTR-ZTBRR6 was a more suitable practice for maintaining system productivity and soil biological health. Discussion: The understanding of the impact of different tillage and residue management practices on productivity, soil biological properties and soil quality index under rice-barley cropping system will help in determining the combination of best conservation agriculture practices for improved soil quality and sustainable production.

Population structure and diversity assessment of barley (Hordeum vulgare L.) introduction from ICARDA.

This study was undertaken to measure the genetic diversity and population structure of 48 barley accessions introduced from ICARDA using 51 polymorphic simple sequence repeat (SSR) markers to select unique parents for breeding. The mean polymorphic information content was 0.491, suggesting high polymorphism for the selected SSR markers among the barley accessions. The population structure indicated a fine genetic base only with two major clusters. All accessions had 100% membership probability in their respective clusters. Analysis of molecular variance revealed that most (78%) of the variation was attributed between populations, while 22% was due to variation among individuals within populations. Neighbour-joining (NJ) tree was constructed using this distance matrix and two major clusters were observed in it. Cluster 1 had all hulled barley accessions and cluster 2 had all hulless barley accessions. Cluster 2 could be further divided into three subclusters. Principal coordinates analysis results were similar to the NJ tree, where the hulled and hulless barley accessions were grouped into separate clusters. This study established the existence of considerable genetic diversity among the 48 tested accessions. The selected genetic resources will be useful for barley breeding in India and other countries.

Hulless barley as a promising source to improve the nutritional quality of wheat products.

In this study, efforts were made to utilize hulless barley (variety BHS352) to enhance the nutritive value of chapatti and biscuit made from wheat flour. Barley flour was added to wheat flour in different ratios (5 to 30%). Antioxidant activity, total phenolic content and ß-glucan content were determined both in flour blends and their products. Changes in physical quality and taste of chapatti and biscuits after blending of hulless barley flour with wheat flour were measured. The chapatti quality score decreased by 15% and biscuit spread factor by 33% after 30% barley flour blending. Significant increase in ß-glucan content and antioxidant activity of flour blends and their products was observed at 30% blending level. The phenolic content increased from 63 to 135 µg for biscuits and 237 to 287 ug GAE/g for chapatti with blending of 30% barley flour.