Bioactive Compounds and Antioxidant Capacity of Valencian Pepper Landraces

Sweet pepper is one of the most important economic fruits with nutritional attributes. In this sense, the nutraceutical value of consumed products is a major concern nowadays so the content of some bioactive compounds and antioxidants (phenols, ascorbic acid, lycopene, carotenoids, chlorophylls, and antioxidant activity) was monitored in 18 sweet pepper landraces at two maturity stages (green and red). All the traits except chlorophylls significantly increased in red fruits (between 1.5- and 2.3-fold for phenols, ascorbic acid, and 2-2-diphenyl-1-picrylhydrazyl (DPPH) inhibition activity, 4.8-fold for carotenoid and 27.4-fold for lycopene content), which suggests that ripening is key for obtaining desired fruit quality. Among landraces, P-44 in green fruits is highlighted for its content in carotenoids, chlorophylls, phenols, and ascorbic acid, and P-46 for its antioxidant capacity and lycopene content. Upon maturity, P-48, P-44, and P-41 presented higher levels of phenols and lycopene, and P-39 of phenols, carotenoid, and DPPH. This work reflects a wide variability in the 18 pepper landraces at bioactive compounds concentration and in relation to fruit ripeness. The importance of traditional landraces in terms of organoleptic properties is emphasized as they are the main source of agricultural biodiversity today and could be helpful for breeders to develop new functional pepper varieties.

Mutation breeding in rice for sustainable crop production and food security in India.

With the inevitable risk posed by global climate change affecting crop yield and the ever-increasing demands of agricultural produce, crop improvement techniques need to be more precise in developing smart crop varieties. The rice crop, a staple food for the majority of the world population, has a significant role to play in alleviating the global hunger problem. With the world population burgeoning at an unprecedented rate, limited fertile land resources, climate change, emerging new races of pests and diseases and consumer preferences for quality attributes, it is imperative to increase crop diversity, and this requires better selection efficiency addressing the challenges of future rice production. Mutation breeding is a fundamental and very successful tool helping to increase crop diversity and allowing plant breeders to exercise their skill in developing desirable crop varieties. The induction of mutations has been used to enhance yield, improve nutritional quality and widen the adaptability of the world's most important crops such as wheat, rice, pulses, millets and oilseeds. India is considered to be one of the primary centres of origin of crop species with the concomitant very high genetic diversity in traditional landraces for different agronomic traits of economic importance. Plant architecture, such as plant height, branching habit (tiller number), leaf shape and patterns, floral and grain traits and quality traits such as aroma, amylose content and cooking quality are of tremendous importance for rice improvement programmes. Traditional landraces of rice have premium grain quality, fetching a premium price, but their cultivation is being marginalized due to their tall stature, proneness to lodging, late maturity and poor yield. Mutation breeding technology has been successfully implemented in rice improvement programmes, which have resulted in the improvement of aromatic rice varieties, such as 'Pusa Basmati 1', 'Dubraj and Jawaphool'. Two high-yielding mutant rice varieties, TCDM-1 ('Trombay Chhattisgarh Dubraj Mutant-1') and TKR Kolam ('Trombay Karjat Rice Kolam'), have been released for cultivation in Chhattisgarh and the Konkan region of Maharashtra. Both these varieties possess dwarf plant stature (110 cm), medium maturity (130 days), premium grain quality and resistance to major pests and diseases. Improvement of other traditional rice varieties is underway which will bring these varieties back into cultivation and help in improving the tribal and marginal farmers' economy.

Assessment of Genetic Diversity in Traditional Landraces and Improved Cultivars of Rice

Background: Rice is the staple food for more than half of the world's population. Rice cultivation needs expansion to meet the increasing food demands across the globe. Genetic diversity is desired for crop breeding because it serves as the backbone for improving cultivars. The process of domestication and modern plant breeding technologies applied to rice has contributed to the erosion of genetic diversity. Current breeding programs have extensively shaped the genetic diversity of elite rice cultivars to no small extent. Results: We explored the genetic diversity of traditional landraces and improved cultivars by inspecting the whole genome SNP markers of 20 rice accessions. We found a higher number of genetic variations (76.70%) and observed heterozygosity (0.024) in landraces than improved cultivars. The principal component analysis also revealed the higher genetic diversity among the landraces. While population structure based on the phylogenetic tree suggested the population's structure according to rice subspecies. The genetic diversity parameter, FST, was applied to estimate the genetic differentiation of rice, which revealed week genetic differentiation (0.121) and nucleotide diversity (0.314) in modern rice cultivars. Genome-wide genetic differentiation (FST) analysis identified the two domesticated genes: Kala4 (pericarp color) and Ghd7 (heading date), and eight improvement genes: Sd1, Ghd8, GW2, NRT1.1b, GW6a, and Hd3a, that coincide with the candidate selective sweeps. Inbreeding depression (0.68617) among the modern cultivars suggests no genetic gain in future breeding efforts and compels exotic material utilization in the breeding programs. Conclusion: These findings demonstrate that modern cultivars have a narrow genetic base compared to landraces. Therefore, exploring the genome of landraces at a large scale to identify the genes responsible for stability and adaptation to abiotic stresses can help design varieties that can survive vulnerable climates.

DNA Fingerprinting and Species Identification Uncovers the Genetic Diversity of Katsouni Pea in the Greek Islands Amorgos and Schinoussa

Pea (P. sativum L.), one of the most important legume crops worldwide, has been traditionally cultivated in Lesser Cyclades since ancient times. The commonly known traditional pea cultivar, ‘Katsouni’, is endemic to the islands of Amorgos and Schinoussa and is of great local economic importance. Despite the widespread cultivation of ‘Katsouni’ in both islands, it is still unknown whether the current Schinoussa and Amorgos pea populations are distinct landraces, and if they have common evolutionary origin. To assist conservation and breeding of the pea crop, the genetic diversity and phylogenetic relationships of 39 pea samples from Amorgos and 86 from Schinoussa were studied using DNA barcoding and ISSR marker analyses. The results indicate that both populations are different landraces with distinct geographical distribution and are more closely related to P. sativum subsp. elatius than the P. abyssinicum and P. fulvum species. Further characterization of the ‘Katsouni’ landraces for functional polymorphisms regarding pathogen resistance, revealed susceptibility to the powdery mildew (Erysiphe pisi DC.). This work represents the first investigation on the genetic diversity and population structure of the ‘Katsouni’ cultivar. Exploiting the local genetic diversity of traditional landraces is fundamental for conservation practices and crop improvement through breeding strategies.

Single-gene resolution of locally adaptive genetic variation in Mexican maize

Threats to crop production due to climate change are one of the greatest challenges facing plant breeders today. While considerable adaptive variation exists in traditional landraces, natural populations of crop wild relatives, and ex situ germplasm collections, separating adaptive alleles from linked deleterious variants that impact agronomic traits is challenging and has limited the utility of these diverse germplasm resources. Modern genome editing techniques such as CRISPR offer a potential solution by targeting specific alleles for transfer to new backgrounds, but such methods require a higher degree of precision than traditional mapping approaches can achieve. Here we present a high-resolution genome-wide association analysis to identify loci exhibiting adaptive patterns in a large panel of more than 4500 traditional maize landraces representing the breadth of genetic diversity of maize in Mexico. We evaluate associations between genotype and plant performance in 13 common gardens across a range of environments, identifying hundreds of candidate genes underlying genotype by environment interaction. We further identify genetic associations with environment across Mexico and show that such loci are associated with variation in yield and flowering time in our field trials and predict performance in independent drought trials. Our results indicate that the variation necessary to adapt crops to changing climate exists in traditional landraces that have been subject to ongoing environmental adaptation and can be identified by both phenotypic and environmental association.

Bio-cultural Diversity and Ethnobotanic Utility of Indigenous Rice (Oryza sativa L.) in Lakhimpur District, Assam, India

The traditional landraces of rice plant had a major role in building socio-economic status of rural poor. The present study deals with the diversity and ethnobotanic significance of indigenous landraces of rice in Lakhimpur district of Assam, India. Altogether, twenty-one indigenous landraces of rice were collected during the present study. Each class having important role to play, the major classes of rice include glutinous, common rice and aromatic rice. Other than being a staple food, rice and its products are still frequently used by rural folk in various festivals, religious and social ceremonies in the form of sweets, cakes, snacks and beverages. Bora-dhan was reported with the highest use value. Based on grain’s qualitative and quantitative traits, the obtained dendrogram contains four different clusters; while, the OTUs (Operational taxonomic unit) present in a cluster display morphological similarity. The dendrogram also illustrated diversified distribution of grains in this region. The study also reveals the profound relationship of people with the traditional landraces of rice. The ethnic farmers should be made aware to promote on-farm conservation of crop diversity, before it is lost under the debris of modernization.