No abstract

Nepal is a part of the world's biodiversity hotspot and ranks the 49 th 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.

In contrast to current knowledge, the B -ring hydroxylation pattern of anthocyanins can be determined by the hydroxylation of leucoanthocyanidins in the 3' position by flavonoid 3'-hydroxylase. The cytochrome P450-dependent monooxygenases flavonoid 3'-hydroxylase (F3'H) and flavonoid 3',5'-hydroxylase (F3'5'H) are key flavonoid enzymes that introduce B-ring hydroxyl groups in positions 3' or 3' and 5', respectively. The degree of B-ring hydroxylation is the major determinant of the hue of anthocyanin pigments. Numerous studies have shown that F3'H and F3'5'H may act on more than one type of anthocyanin precursor in addition to other flavonoids, but it has been unclear whether the anthocyanin precursor of the leucoanthocyanidin type can be hydroxylated as well. We have investigated this in vivo using feeding experiments and in vitro by studies with recombinant F3'H. Feeding leucoanthocyanidins to petal tissue with active hydroxylases resulted in anthocyanidins with increased B-ring hydroxylation relative to the fed leucoanthocyanidin, indicating the presence of 3'-hydroxylating activity (in Petunia and Eustoma grandiflorum Grise.) and 3',5'-hydroxylating activity (in E. grandiflorum Grise.). Tetcyclacis, a specific inhibitor of cytochrome P450-dependent enzymes, abolished this activity, excluding involvement of unspecific hydroxylases. While some hydroxylation could be a consequence of reverse catalysis by dihydroflavonol 4-reductase (DFR) providing an alternative substrate, hydroxylating activity was still present in fed petals of a DFR deficient petunia line. In vitro conversion rates and kinetic data for dLPG (a stable leucoanthocyanidin substrate) were comparable to those for other flavonoids for nine of ten recombinant flavonoid hydroxylases from various taxa. dLPG was a poor substrate for only the recombinant Fragaria F3'Hs. Thus, the B-ring hydroxylation pattern of anthocyanins can be determined at all precursor levels in the pathway.

Diversity in fruit genetic resources in Nepal is contributed by wild, indigenous and exotic sources. This study was carried out to bring together the available fruit species and cultivars at various stations of Department of Agriculture (DoA), Nepal Agricultural Research Council (NARC), Agriculture and Forest University (AFU) and private farms until the Fiscal Year 2017/2018. Altogather there were 47 species of fruits from tropical zone of Terai (Tarahara, Janakpur, Sarlahi, Parwanipur and Khajura) to cold temperature zone of high hills (Marpha, Rajikot and Satbanj) across the country. Apple diversity was found at Horticulture Research Station, Rajikot, Jumla and has introduced 25 spur type cultivars. National Citrus Research Programme (NCRP), Dhankuta was citrus most diversity areas and has maintained 130 exotic and indigenous germplasms of citrus species followed by NCFD, Kirtipur. Mango diversity was noted at RARS, Tarahara (16 cultivars), RARS, Parwanipur (25 cultivars), Farm of DoA-Sarlahi (30 cultivars), Farms of DoA-Janakpur (18 cultivars), AFU-Rampur (17 cultivars). Some of the private nurseries like Everything Organic Nursery, Patlekhet, Kavre and international organization like Technology Demonstration Centre of ICIMOD, Godawari, Lalitpur were also found to be a diversity centre of many exotic and indigenous germplasms of fruit species. These indigenous fruit genetic resources were also used to develop varieties such as Sunkagati-1 and Sunkagati-2 and Tehrathum Local of acid lime, Khoku Local of mandarin orange, 'Malbhog' of banana which were notified by the National Seed Board, SQCC. The unique fruit genetic resources were "Pharping Local" (Asian sand pear), "Sindhuli Junar" (sweet orange), "Dhankuta Local" and "Manakamana Local" (mandarin), Local Malbhog (banana), Bhaktapure Lapsi (Nepalese hog plum) etc. which have superior traits than exotic fruits. Unique and wild fruit species were yellow, black and red raspberries (Rubus ellipticus, R. foliolosus and R. acuminatus respectively), bale (Aegle marmelos), pummelo (Citrus grandis), citron (Citrus medica), sweet lime (Citrus limettoides), butter tree or chiuri (Basia buttyacea), tamarind (Tamarindus indica), black plum (Syzygium cumini), wild apple (Mallus baccata), rough lemon (Citrus jambhiri), bayberry (Myrica esculanta), edimayal (Pyrus pashia), black and white ebony (Diospyrus malbarica), wild species of olive (Olea ferruginea and O. glandulifera), wild kiwifruit (Actinidia callosa) etc. Most of the diversity studies were based on phenotypic descriptions. We believe that the number of species and genotypes listed in this article would be increased if detail survey is further carried out. Way forward to utilize these valuable genetic resources has also been discussed in this manuscript.;f/f+ z g] kfnsf] kmnkm" n ju{ sf] cfg' j+ lzs ;| f] tdf ljljwtf oxfsf] h+ unL, /} yfg] , :yflgo / ljb] zL ;| f] tx¿n] of] ubfg k' of{ pF 5g\ . g] kfn ;/sf/sf] s[ lif ljefusf kmfd{ , g] kfn s[ lif cg' ;Gwfg kl/ifbsf kmfd{ -gfs{ _, s[ lif tyf jg ljZjljBfno / lghL kmfd...

Nepal has spent about six decades on fruit development and research in different species. Fruit breeding particularly local and exotic germplasm collection started after 1950s and has gained momentum after the formation of commodity programme in 1972 AD. Major researches in the past were focused on indigenous and exotic genotype collection, evaluation, selection, propagation protocol standardization and adoptive trials. Some good ground works have already been done in major fruits such as apple, pear, plum, persimmon, kiwifruit, citrus, litchi, guava, pomegranate, walnut, papaya, banana and mango. The major public institutions involved in fruit breeding are Nepal Agricultural Research Council (NARC) following Agriculture and Forestry University. Some of the private nurseries like Everything Organic Nursery, Kavre and Technology Demonstration Centre of ICIMOD, Lalitpur were also involved in introduction and maintenance of indigenous and exotic fruit species. National Centre for Fruit Development, Kirtipur; Tropical Region Horticulture Centre, Nawalpur; Temperate Horticulture Farm, Satbanj, and Horticulture Farm, Marpha collected many local and exotic fruits and maintained at field gene bank. Horticulture Research Station, Rajikot has introduced 25 spur type apple cultivars and maintained in field gene bank. National Citrus Research Programme, Paripatle has introduced, collected and maintained 130 genotypes including exotic and indigenous landraces of citrus. Two varieties of acid lime ‘Sunkagati-1’ and ‘Sunkagati-2’ have been released and one variety ‘Terhathum Local’ has been registered. ‘Khoku Selection’ of mandarin orange has also been registered. Banana varieties 'Malbhog', 'Willium Hybrid' and 'G9' has been selected by participatory varietal selection and registered.  To strengthen fruit breeding in the nation, NARC needs to be restructured with special focus on fruit researches. Establishment of national fruit commodity programs along with establishment of Tropical Fruit Research Station in Province 2 and Temperate Fruit Research Station in Province 5 at national level can streamline NARC's fruit breeding researches.