Crop genetic diversity is the most important factor for a long-term sustainable production system. Breeding and production strategies for developing and growing uniform and homogenous varieties have created many problems. Such populations are static and very sensitive to unpredictable stresses. In Nepal, more than 80% of the seed system is informal, which has contributed greatly to creating and maintaining genetic diversity within the field. This paper aims to assess and present the approaches and advantages of increased crop genetic diversity in the fields, based on the experiences of implementing on-farm conservation activities carried out in Nepal for last two decades. Some of the evidence has been derived from an ongoing evolutionary plant breeding (EPB) project being implemented in Nepal. The information is supplemented with field assessments, focus group discussion, and a literature review. The major approaches to increase crop genetic diversity are evolutionary plant breeding, cultivar mixture, landrace enhancement, informal seed systems, the bulk method, diversifying the seed sources, participatory plant breeding, open pollination, etc. EPB and cultivar mixture are very simple and effective approaches to increase crop genetic diversity at field level. The involvement of farmers in these approaches helps to accelerate the population improvement, maintaining the higher degree of genetic diversity. The major advantages of increased crop genetic diversity are seed maintenance by farmers themselves, minimal risk of crop failure, resilience to unpredictable stresses, increased amount of diversified nutrition, production increment, ease of producing organically, etc. However, there are some issues and problems associated with mixtures and intra-varietal diversity; for example, not being able to harvest by machine, maturing at a different date, difficulty in maintaining seeds and registration, etc. Crop genetic diversity should be considered as a sustainable approach for a climate-resilient and self-dependent production system. The higher the genetic diversity in farming land, the more chance of receiving multiple benefits in the agriculture system.

Nepal ranks 49th in the world for biodiversity richness. Among 577 cultivated species in Nepal, 484 are indigenous and 93 are introduced. About 85% of these cultivated crop species are neglected and underutilized. The use of landraces in research and breeding is only about 5%. Just three crops, viz., rice (Oryza sativa L.), wheat (Triticum aestivum L.), and maize (Zea mays L.), cover 83% of the total cultivated area. Monogenotyping (the use of genotypes containing genetic material from a single parent) field, kitchen, market, and food items have triggered new problems. In Nepal, neglected and underutilized species (NUS) are those crop species that are not included in formal research, education, and development. Future smart crops (FSCs) are NUS that are known for their high potential for food, nutritional security, and high adaptability to changing climate. FSCs have tremendous potential to contribute to food security, nutrition, dietary and culinary diversification, health, income generation, and are well adapted to marginal soils and harsh climatic conditions. To manage (conserve and utilize) all agricultural genetic resources, including NUS and FSC, 25 conservation methods, along with more than 30 good practices, have been practiced in Nepal. Many of the NUS have not been adequately studied for their nutritional value and adaptability to harsh environments. This paper provides current status and potential of NUS and FSCs for developing site-specific staple, nutritious, diversified products and climate-resilient varieties. This review also addresses the prospects of long-term conservation and sustainable agriculture systems in Nepal.

Nepal is a part of the world’s biodiversity hotspot and ranks the 49th in the world for biodiversity. Agrobiodiversity and its conservation status were studied through literature review, field survey, key informant survey and focus group discussion. Results of field implementation of some good practices and action research were also documented. Among 24,300 total species in the country, 28% are agricultural genetic resources (AGRs), termed as agrobiodiversity. Agrobiodiversity has six components (crops, forages, livestock, aquatic, insects and microorganisms) and four sub-components (domesticated, semi-domesticated, wild relatives and wild edible) in Nepal. Agrobiodiversity on each component exists at agroecosystem, species, variety/breed/biotype/race/strain, genotype and allele levels, within an altitude range from 60 to 5,000 masl. There are 12 agroecosystems supporting 1026 species under crop component, 510 under forage, 35 under livestock, 250 under the aquatic animal, 17 under aquatic plant, 3,500 under insect and 800 under microorganism. An estimated loss of agrobiodiversity is 40%, however, farmers have reported up to 100% loss of AGRs in some areas for a particular species. Conservation of agrobiodiversity has been initiated since 1986. Four strategies namely ex-situ, on-farm, in-situ and breeding have been adopted for conservation and sustainable utilization of AGRs. Eighty good practices including process, methods and actions for managing agrobiodiversity have been in practice and these practices come under five conservation components (sensitization, method and approach, accelerator, value and enabling environment). Within the country, 18,765 accessions of AGRs have been conserved in different kinds of banks. A total of 24,683 accessions of Nepalese crops, forages and microbes have been conserved in different international and foreign genebanks. Some collections are conserved as safety duplication and safety backup in different CGIARs’ banks and World Seed Vault, Korea. Two global databases (GENESYS and EURISCO) have maintained 19,200 Nepalese accessions. Geographical Information System, Climate Analog Tool and biotechnological tools have been applied for better managing AGRs. Many stakeholders need to further concentrate on the conservation and utilization of AGRs. Global marketing of some native AGRs is necessary for sustaining agriculture and attracting young generations as well as conserving them through use.

Naked barley is a traditional, climate-resilient and highly nutritious crop of the high mountains of Nepal. Knowledge of agro-morphological diversity among the naked barely genotypes is fundamental for their efficient utilization in plant breeding schemes and effective conservation programs. The primary objective of this study is phenotypic characterization and diversity assessment of naked barley landraces in Nepal for pre-breeding purposes. Data on quantitative and qualitative traits of 25 naked barley landraces from diversity blocks established across the four mountainous locations of Nepal (Humla, Jumla, Dolakha and Lamjung) were subjected to calculation of descriptive statistics and multivariate analysis (UPGMA cluster analysis/principal component analysis). Frequency distribution of various categories of qualitative traits and Shannon–Weaver diversity indices were computed. The UPGMA cluster analysis using both quantitative and qualitative traits individually categorized the 25 naked barley landraces in five clusters in each case with no distinct regional grouping patterns in such a way that the landraces from same or adjacent regions of origin and collection amassed in different clusters. NGRC04894, Lamjung Local, NGRC02306, NPGR1579, NGRC02327 and NPGR1579 exhibited morphoagronomical superiority and potentiality for utilization as genitors in crop improvement programs. Principal component analysis revealed the quantitative traits, viz. grain yield, plant height and earliness, and qualitative traits, viz. grain color, overall phenotypic performance, lemma awn/hood and lemma awn barbs, to be the principal discriminatory characteristics of the Nepalese naked barley landrace collection. The Shannon–Weaver diversity index (H′) ranged from 0.32 to 0.99 with a mean value of 0.73, inferring tremendous diversity in the collection for the qualitative traits. The marked diversity observed among the Nepalese naked barley landraces could be utilized in crop improvement for various traits. The information generated complements the robust breeding program of competitive, stable and climate-resilient varieties of end users’ preferences in different mountainous agro-ecologies and also bolsters the employment of innovative and proven participatory plant breeding approach using diversity kits and informal research and development kits to expand and promote the varietal choice options for expeditious benefits to the farmers in the high mountains, considering that only one naked barley variety, viz. Solu Uwa, has been released in Nepal to date.

Acid lime (Citrus aurantifolia (Christm.) Swingle) is an important fruit crop, which has high commercial value and is cultivated in 60 out of the 77 districts representing all geographical landscapes of Nepal. A lack of improved high-yielding varieties, infestation with various diseases, and pests, as well as poor management practices might have contributed to its extremely reduced productivity, which necessitates a reliable understanding of genetic diversity in existing cultivars. Hereby, we aim to characterize the genetic diversity of acid lime cultivars cultivated at three different agro-ecological gradients of eastern Nepal, employing PCR-based inter-simple sequence repeat (ISSR) markers. Altogether, 21 polymorphic ISSR markers were used to assess the genetic diversity in 60 acid lime cultivars sampled from different geographical locations. Analysis of binary data matrix was performed on the basis of bands obtained, and principal coordinate analysis and phenogram construction were performed using different computer algorithms. ISSR profiling yielded 234 amplicons, of which 87.18% were polymorphic. The number of amplified fragments ranged from 7–18, with amplicon size ranging from ca. 250–3200 bp. The Numerical Taxonomy and Multivariate System (NTSYS)-based cluster analysis using the unweighted pair group method of arithmetic averages (UPGMA) algorithm and Dice similarity coefficient separated 60 cultivars into two major and three minor clusters. Genetic diversity analysis using Popgene ver. 1.32 revealed the highest percentage of polymorphic bands (PPB), Nei’s genetic diversity (H), and Shannon’s information index (I) for the Terai zone (PPB = 69.66%; H = 0.215; I = 0.325), and the lowest of all three for the high hill zone (PPB = 55.13%; H = 0.173; I = 0.262). Thus, our data indicate that the ISSR marker has been successfully employed for evaluating the genetic diversity of Nepalese acid lime cultivars and has furnished valuable information on intrinsic genetic diversity and the relationship between cultivars that might be useful in acid lime breeding and conservation programs in Nepal.