Evaluation of fodder yield and fodder quality in sorghum and its interaction with grain yield under different water availability regimes

Sorghum is widely grown as a failsafe crop in semi-arid regions particularly in post rainy season. Though the effect of drought on crop performance is studied widely there are few studies illustrating the association of fodder quality and agronomic traits under drought. To study the interactions we evaluated a set of 24 cultivars under drought for three years in post rainy season. The effect of drought was evident in delayed flowering (by 2 days) and reduce plant height (by 0.98 cm) compared to control. The fodder digestibility traits were reduced (in vitro organic matter digestibility by 2.25 times) under drought. All the plant growth and yield parameters recorded higher heritability compared to fodder quality parameters (<0.75) in most of the season in both control and stress environments. The scatter plot showed best (ICSV700-P10, N13, PB15881-3, SP 2417-P3) and poor (296B, ICSB377-P1, ICSV1, IS9830) performing entries in control and stress plots. The agronomic and the fodder quality traits have shown no significant relationship between them, hence independent association can be utilized to breed for desirable traits. Identification of contrasting lines could be the key to identify genes controlling the fodder quality traits under drought

Genetic dissection and quantitative trait loci mapping of agronomic and fodder quality traits in sorghum under different water regimes

Livestock provides an additional source of income for marginal cropping farmers, but crop residues that are used as a main source of animal feed are characteristically low in digestibility and protein content. This reduces the potential livestock product yield and quality. The key trait, which influences the quality and the cost of animal feed, is digestibility. In this study, we demonstrate that sorghum breeding can be directed to achieve genetic gains for both fodder biomass and digestibility without any trade-offs. The genotypic variance has shown significant differences for biomass across years (13,035 in 2016 and 3,395 in 2017) while in vitro organic matter digestibility (IVOMD) showed significant genotypic variation in 2016 (0.253) under drought. A range of agronomic and fodder quality traits was found to vary significantly in the population within both the control and drought conditions and across both years of the study. There was significant genotypic variance (σg(2)) and genotypic × treatment variance (σgxt(2)) in dry matter production in a recombinant inbred line (RIL) population in both study years, while there was only significant σg(2) and σgxt(2) in IVOMD under the control conditions. There was no significant correlation identified between biomass and digestibility traits under the control conditions, but there was a positive correlation under drought. However, a negative relation was observed between digestibility and grain yield under the control conditions, while there was no significant correlation under drought population, which was genotyped using the genotyping-by-sequencing (GBS) technique, and 1,141 informative single nucleotide polymorphism (SNP) markers were identified. A linkage map was constructed, and a total of 294 quantitative trait loci (QTLs) were detected, with 534 epistatic interactions, across all of the traits under study. QTL for the agronomic traits fresh and dry weight, together with plant height, mapped on to the linkage group (LG) 7, while QTL for IVOMD mapped on to LG1, 2, and 8. A number of genes previously reported to play a role in nitrogen metabolism and cell wall-related functions were found to be associated with these QTL

Genomics breeding approaches for developing Sorghum bicolor lines with stress resilience and other agronomic traits

Sorghum, also known as great millet, is a major cereal crop that feeds over 500 million people in more than 100 countries, especially in Africa and Asia. It can grow well under harsh environmental conditions, such as drought, heat, salinity, and soils that are nutritionally poor. The crop is water- and nitrogen-efficient with C4 photosynthesis system and a relatively small genome of about 730 Mb. Its genome has been sequenced and annotated, revealing significant genetic variation and genomics resources. Despite being drought tolerant, there is a great degree of variation among the diverse lines of germplasm for drought and drought associated traits, and hence resilience to drought and other stresses need to be studied through the integration of phenomics and genomics technologies. There is an urgent need to adopt advanced genomics and high-throughput technologies to find candidate genes and alleles for crop traits, develop molecular markers and genomic selection (GS) models, create new genetic variation and design sorghum ideotypes that suit to the changing climate

Overexpression of RNA ‐binding bacterial chaperones in rice leads to stay‐green phenotype, improved yield and tolerance to salt and drought stresses

Genes encoding bacterial cold shock proteins A (CspA, 213 bp) and B (CspB, 216 bp) were isolated from Escherichia coli strain K12, which showed 100% homology with gene sequences isolated from other bacterial species. In silico domain, analysis showed eukaryotic conserved cold shock domain (CSD) and ribonuclease-binding domain (RBD) indicating that they bind to RNA and are involved in temperature stress tolerance. Overexpression of these two genes in E. coli resulted in higher growth in presence of 200 mM NaCl and 300 mM mannitol. Western blot confirmed the translational products of the two genes. Seedlings of indica rice were transformed with Agrobacterium tumefaciens containing pCAMBIA1301 CspA and CspB genes. Transgene integration was confirmed by β-glucuronidase (GUS) histochemical assay, polymerase chain reaction (PCR) amplification, and gene copy number by Southern blotting. Chlorophyll, proline, Na+, and K+ contents were higher in transgenics exposed to 150 mM NaCl and drought (imposed by withholding water) stresses during floral initiation stage. Catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (GPX) activities increased, while malondialdehyde (MDA) content was low in transgenics. Transgenics displayed increased root, shoot, and panicle lengths, root dry mass, and a distinct stay-green (SGR) phenotype. Higher transcript levels of CspA, CspB, SGR, chlorophyllase, isopentenyl adenine transferase 1 (IPT1), 9-cis-epoxycarotenoid dioxygenase (NCED), SOD, and sirtuin 1 (SIRT1) genes were observed in transgenics compared to wild type plants (WT) under multiple stresses. Present work indicates that bacterial chaperone proteins are capable of imparting SGR phenotype, salt and drought stress tolerance alongside grain improvement