What drives the adoption of fodder innovation(s) in a smallholder dairy production system? Evidence from a cross-sectional study of dairy farmers in India

The study in India involving 384 households found that 42.7% of dairy farmers adopted new forage varieties when varieties were released. The farmer’s resources, their caste, access to markets for milk and price received for milk had positive effects on the decision to adopt. Management of farms by women had negative effects on the adoption decision. Increased forage yield and ease of propagation and establishment were important reasons for adoption of varieties, e.g. the relative advantage of pearl millet × Napier grass (Cenchrus americanus × C. purpureus) vs. hedge lucerne (Desmanthus virgatus). Thus, researchers need to address these issues when developing new germplasm, if farmers are to readily adopt new varieties, especially in the case of resource-poor farmers.

CRISPR-Cas9 Gene Editing for Fruit and Vegetable Crops: Strategies and Prospects

Fruit and vegetable crops are rich in dietary fibre, vitamins and minerals, which are vital to human health. However, many biotic stressors (such as pests and diseases) and abiotic stressors threaten crop growth, quality, and yield. Traditional breeding strategies for improving crop traits include a series of backcrosses and selection to introduce beneficial traits into fine germplasm, this process is slow and resource-intensive. The new breeding technique known as clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein-9 (Cas9) has the potential to improve many traits rapidly and accurately, such as yield, quality, disease resistance, abiotic stress tolerance, and nutritional aspects in crops. Because of its simple operation and high mutation efficiency, this system has been applied to obtain new germplasm resources via gene-directed mutation. With the availability of whole-genome sequencing data, and information about gene function for important traits, CRISPR-Cas9 editing to precisely mutate key genes can rapidly generate new germplasm resources for the improvement of important agronomic traits. In this review, we explore this technology and its application in fruit and vegetable crops. We address the challenges, existing variants and the associated regulatory framework, and consider future applications.

Transcriptional insights into sugarcane aquaporin genes under water deficit conditions

Water deficit in soil during formative growth stage adversely hinders the crop productivity. Plant develop a key chain of mechanisms to cope these strains. Characterization of genotypes under water deficit will provide the basis for breeding new germplasm for efficient utilization of water and nutrients and adaptation to water stress. To achieve this, two tolerant (Co 98014 and Co 0118) and two sensitive (CoJ 85 and Co 89003) sugarcane genotypes were assessed for antioxidant responses followed by differential expression of three aquaporin genes (ShPIP2-1, ShPIP-5 and ShPIP2-6) under two water deficit conditions. The MDA and H2O2 contents were significantly higher (p<0.05) in sensitive genotypes as compared to tolerant ones, whereas SOD activity was higher (p<0.05) in tolerant than sensitive genotypes. The transcript analysis of AQPs reveals upregulation of ShPIP2;5, whereas down-regulation of ShPIP2;1 and ShPIP2;6 when plants were imposed to water deficit conditions. The findings under study suggested the role of PIP2 AQPs in regulation of plant water status under water deficit conditions.

Genome-Wide Identification of Soybean ABC Transporters Relate to Aluminum Toxicity

ATP-binding cassette (ABC) transporter proteins are a gene super-family in plants and play vital roles in growth, development, and response to abiotic and biotic stresses. The ABC transporters have been identified in crop plants such as rice and buckwheat, but little is known about them in soybean. Soybean is an important oil crop and is one of the five major crops in the world. In this study, 255 ABC genes that putatively encode ABC transporters were identified from soybean through bioinformatics and then categorized into eight subfamilies, including 7 ABCAs, 52 ABCBs, 48 ABCCs, 5 ABCDs, 1 ABCEs, 10 ABCFs, 111 ABCGs, and 21 ABCIs. Their phylogenetic relationships, gene structure, and gene expression profiles were characterized. Segmental duplication was the main reason for the expansion of the GmABC genes. Ka/Ks analysis suggested that intense purifying selection was accompanied by the evolution of GmABC genes. The genome-wide collinearity of soybean with other species showed that GmABCs were relatively conserved and that collinear ABCs between species may have originated from the same ancestor. Gene expression analysis of GmABCs revealed the distinct expression pattern in different tissues and diverse developmental stages. The candidate genes GmABCB23, GmABCB25, GmABCB48, GmABCB52, GmABCI1, GmABCI5, and GmABCI13 were responsive to Al toxicity. This work on the GmABC gene family provides useful information for future studies on ABC transporters in soybean and potential targets for the cultivation of new germplasm resources of aluminum-tolerant soybean.

OsGATA16, a GATA Transcription Factor, Confers Cold Tolerance by Repressing OsWRKY45–1 at the Seedling Stage in Rice

Background Cold stress is the main abiotic stress in rice, which seriously affects the growth and yield of rice. Identification of cold tolerance genes is of great significance for rice to solve these problems. GATA-family transcription factors involve diverse biological functions, however, their role in cold tolerance in rice remains unclear. Results In this study, a GATA-type zinc finger transcription factor OsGATA16, which can improve cold tolerance, was isolated and characterized from rice. OsGATA16 belongs to OsGATA subfamily-II and contains 11 putative phosphorylation sites, a nuclear localization signal (NLS), and other several conserved domains. OsGATA16 was expressed in all plant tissues, with the strongest in panicles. It was induced by cold and ABA treatments, but was repressed by drought, cytokinin and JA, and acted as a transcriptional suppressor in the nucleus. Overexpression of OsGATA16 improves cold tolerance of rice at seedling stage. Under cold stress treatments, the transcription of four cold-related genes OsWRKY45–1, OsSRFP1, OsCYL4, and OsMYB30 was repressed in OsGATA16-overexpressing (OE) rice compared with wild-type (WT). Interestingly, OsGATA16 bound to the promoter of OsWRKY45–1 and repressed its expression. In addition, haplotype analysis showed that OsGATA16 polarized between the two major rice subspecies japonica and indica, and had a non-synonymous SNP8 (336G) associated with cold tolerance. Conclusion OsGATA16 is a GATA transcription factor, which improves cold tolerance at seedling stage in rice. It acts as a positive regulator of cold tolerance by repressing some cold-related genes such as OsWRKY45–1, OsSRFP1, OsCYL4 and OsMYB30. Additionally, OsGATA16 has a non-synonymous SNP8 (336G) associated with cold tolerance on CDS region. This study provides a theoretical basis for elucidating the mechanism of cold tolerance in rice and new germplasm resources for rice breeding.

Stevia rebaudiana germplasm characterization using microsatellite markers and steviol glycosides quantification by HPLC

Stevia rebaudiana Bertoni, Asteraceae, is an herbaceous perennial plant native to Paraguay. This species is considered since ancient times a medicinal plant with important bioactive compounds and pharmacologic and food properties, namely diterpenes glycosides. The high natural sweetener potential stevioside and rebaudioside A produced by S. rebaudiana plants are suitable sucrose substitutes, and their obtention is influenced by environmental, phytosociological, and genetic factors. The plants’ genetic profile and sweet potential depiction are needed for suitable plant selection for improvement and deployment. Thirty-one S. rebaudiana accessions grown in the same plot where leaves samples were collected in early 2019, were genotyped using six microsatellite markers, including two steviol glycosides biosynthesis functionally involved markers. Additionally, an aqueous extract of each sample was obtained in a water bath and purified by SPE for stevioside and rebaudioside A quantification by normal phase HPLC. Stevioside and rebaudioside A contents varied between 0.53–7.36% (w w−1) and 0.37–3.60% (w w−1), respectively. Two genotypes displayed interesting ratios of rebaudioside A/stevioside (number 3 and 33). The level of genetic similarity between genotypes was tested through a pairwise similarity coefficient, and two groups of individuals had the same fingerprinting. Strong relatedness was found within genotypes, possibly due to cloning, thus, influx of new germplasm ought to be made to prevent mating between relatives, and for further selection and genetic improvement.

A New Way of Rice Breeding: Polyploid Rice Breeding

Polyploid rice, first discovered by Japanese scientist Eiiti Nakamori in 1933, has a history of nearly 90 years. In the following years, polyploid rice studies have mainly focused on innovations in breeding theory, induction technology and the creation of new germplasm, the analysis of agronomic traits and nutritional components, the study of gametophyte development and reproduction characteristics, DNA methylation modification and gene expression regulation, distant hybridization and utilization among subspecies, species and genomes. In recent years, PMeS lines and neo-tetraploid rice lines with stable high seed setting rate characteristics have been successively selected, breaking through the bottleneck of low seed setting rate of polyploid rice. Following, a series of theoretical and applied studies on high seed setting rate tetraploid rice were carried out. This has pushed research on polyploid rice to a new stage, opening new prospects for polyploid rice breeding.

Transcriptional insights into sugarcane aquaporin genes under water deficit conditions

Water deficit in soil during formative growth stage adversely hinders the crop productivity. Plant develop a key chain of mechanisms to cope these strains. Characterization of genotypes under water deficit will provide the basis for breeding new germplasm for efficient utilization of water and nutrients and adaptation to water stress. To achieve this, two tolerant (Co 98014 and Co 0118) and two sensitive (CoJ 85 and Co 89003) sugarcane genotypes were assessed for antioxidant response followed by differential expression of three aquaporin genes (ShPIP2-1, ShPIP-5 and ShPIP2-6) under two water deficit conditions. The MDA and H2O2 contents were significantly higher (p < 0.05) in sensitive genotypes as compared to tolerant ones, whereas SOD activity was higher (p < 0.05) in tolerant than sensitive genotypes. The transcript analysis of AQPs reveals upregulation of ShPIP2;5, whereas down-regulation of ShPIP2;1 and ShPIP2;6 when plants were imposed to water deficit conditions. The findings under study suggested the role of PIP2 AQPs in regulation of plant water status under water deficit conditions.

Evaluation of resistance to wheat stem rust and identification of resistance genes in wheat lines from Heilongjiang province

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, (Pgt) is a devastating disease in wheat production. The disease has been effectively controlled since the 1970s due to the widespread use of the Sr31 resistance gene. However, Sr31 has lost its effectiveness following the emergence and spread of the Ug99 race variants. Therefore, there is an urgent global effort to identify new germplasm resources effective against those races. In this study, the resistance to Pgt of 95 wheat advance lines from Heilongjiang Province was evaluated using three predominant races of Pgt, 21C3CTTTM, 34C0MKGSM, and 34C3MTGQM, in China at the seedling and adult plant stage. The presence of 6 Sr genes (Sr2, Sr24, Sr25, Sr26, Sr31, and Sr38) was evaluated using linked molecular markers. The results showed that 86 (90.5%) wheat lines had plant stage resistance to all three races. Molecular marker analysis showed that 24 wheat lines likely carried Sr38, 15 wheat lines likely carried Sr2, 11 wheat lines likely carried Sr31, while none of the wheat lines carried Sr24, Sr25, or Sr26. Furthermore, six out of the 95 wheat lines tested carried both Sr2 and Sr38, three contained both Sr31 and Sr38, and two wheat lines contained both Sr2 and Sr31. Wheat lines with known Sr genes may be used as donor parents for further breeding programs to provide resistance to stem rust.

Development and Characterization of Wheat-Agropyron cristatum Introgression Lines Induced by Gametocidal Genes and Wheat ph1b Mutant

The P genome of Agropyron cristatum Gaertn. contains many desirable genes that can be utilized as genetic resources to improve wheat. In this research, we used both the gametocidal chromosome 2Cc and the pairing homologous gene (Ph1b) mutant to induce structural aberrations and translocations between wheat and the 4P, 5P, and 6P genome chromosomes. By using the two approaches, a total of 19 wheat-A. cristatum translocations have been identified, in which 13 were induced by the Triticum aestivum cv. Chinese Spring (CS) ph1b mutant (CS ph1b) and six were induced by gametocidal chromosome 2Cc from Aegilops cylindrica Host. The wheat-4P, -5P and -6P A. cristatum translocations were characterized by in situ hybridization and by a set of conserved orthologous set (COS) molecular markers. The aberrations included centromeric translocations, terminal translocations, dicentric translocations, and deletions. The average induction frequency of chromosome structural aberrations was 10.9% using gametocidal 2Cc chromosome and 8.8% using ph1b mutant. The highest frequency obtained was for chromosome 4P using both approaches. All the wheat-A. cristatum translocation lines obtained were valuable for identifying A. cristatum chromosome 4P, 5P, and 6P related genes. In addition, these lines provided genetic resources and new germplasm accessions for the genetic improvement of wheat.