This study was conducted to assess the genetic variability and correlation of phenotypic characteristics in 12 tomato (Solanum lycopersicum L.) genotypes including 11 WorldVeg and one commercial variety (Pusa Ruby) in Terai (plain) region of Nepal in 2021–2022. This experiment was laid out in a randomized complete block design with three replications. The phenotypic traits, including days to 50% flowering, plant vigor and height, fruit number/plant, fruit yield, fruit weight and diameter, fruit firmness and fruit pericarp thickness, and total soluble solids (TSS) content of the fruits, were studied. Analysis of variance revealed significant differences among the genotypes for all the traits except for plant vigor. The genotype of AVTO1705 resulted the highest fruit yield (2.9 kg/plant) than Pusa Ruby, a commercial check (0.5 kg/plant). The phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all the traits and PCV values were maximum for the number of fruits, fruit yield, and fruit weight. High PCV, GCV, and genetic advance (GA) were observed for yield, fruit weight, and plant height, respectively, indicating the additive gene effect. High heritability for fruit yield/plant and plant height inferred the phenotypic selection for their genetic improvement. Fruit yield was significantly (P<0.05) positively correlated with the fruit number and fruit weight, and direct selection of these traits are reliable for yield improvement in tomato.

In Nepal, about 73% of the vegetable production area is estimated to be covered by hybrid varieties. Most of the hybrid seeds in vegetable crops are imported from abroad. Considering the demand for hybrid vegetable varieties, the National Horticulture Research Centre (NHRC), Khumaltar, Lalitpur has started hybrid breeding of vegetables using a conventional approach since the fiscal year 2003/04. With this effort, the tomato hybrid ‘Srijana’ was developed and registered in 2010. This variety was estimated to cover about 35% of the total tomato cultivated area. Two tomato hybrids, namely ‘Khumal Hybrid Tomato-2 (HRA14 × HRD7) and ‘Khumal Hybrid Tomato-3’ (HRA20 × HRD2), showed good performance and were released in the National Seed Board in 2021. It was found that the heterosis for the yield was 87% in ‘Khumal Hybrid Tomato-2’ and 95% in ‘Khumal Hybrid Tomato-3’ with a potential yield of 70 MT/ha and 60 MT/ha, respectively, under open field conditions. Similarly, a comparative study of 7 tomato hybrids at different research stations was carried out and it showed that F1 (HRA13 × HRD7) could be a potential hybrid for the western region with a potential productivity of 116.8 MT/ha under a protected cultivation system. Hybrid breeding of cucumber was also initiated in the fiscal year 2007/08. A total of 12 crosses in cucumber were performed and two hybrids F1 (HRDCUC004 x RDCUC001), 107 MT/ha and F1 (HRDCUC009 × HRDCUC003) 150 MT/ha were found promising. Hybrid breeding in brinjal, hot pepper and bitter gourd has also been started. Furthermore, key problems and way forward to strengthen hybrid vegetable breeding in Nepal were also discussed.

This study was carried out to select the suitable and high leaf yielding broadleaf mustard genotypes for the mid-hill conditions of Nepal. We evaluated seven germplasms of broadleaf mustard (Brassica juncea var. rugosa (L.) Czern.) namely, ‘HRDBLM001’, ‘HRDBLM004’, ‘HRDBLM007’, ‘HRDBLM009’, ‘HRDBLM010’, ‘Marpha Chauda Pat’, and ‘Khumal Chauda Pat’ in the field of the National Horticulture Research Centre, Khumaltar under Nepal Agricultural Research Council during the winter season of two consecutive years, 2019 and 2020. The germplasms were collected from the local diversity centres in the country. The experiment was laid out in the Randomized Complete Block Design (RCBD) in three replications per treatment. Seeding was done in September, and 28-day-old seedlings were transplanted in the field. The results obtained from the two consecutive seasons revealed that plant vigour was found to be greater in ‘HRDBLM010’ and ‘Khumal Chauda Pat’ (4.7 in the 1 to 5 scale score). The highest leaf weight (65.1 g) was found in ‘HRDBLM010’, followed by ‘HRDBLM007’ (45.6 g) and ‘Khumal Chauda Pat’ (40.9 g). The highest number of leaves was produced by ‘HRDBLM004’ (50 leaves per plant), while leaf weight per plant was the highest in ‘HRDBLM010’ (691.1 g per plant) followed by ‘HRDBLM004’ (535.4 g per plant). Genotype ‘HRDBLM010' produced the highest leaf yield (54.52 MT ha-1), followed by 'HRDBLM004' (44.28 MT ha-1) and ‘HRDBLM007’ (41.65 MT ha-1). Thus, these three germplasms showed superiority among the seven tested germplasms and they could be recommended for cultivation in the mid-hill conditions of Nepal.

This study was done to characterize the anther derived regenerants (R1) including haploids and spontaneous diploids of minipaprika (cvs.‘Vine sweet-red’ ‘Vine sweet-yellow’ and ‘Vine sweet-orange’) in glasshouse. Eleven haploids (three, seven and one from red, yellow and orange, respectively) and sixteen spontaneous diploids (five, nine and two from red, yellow and orange, respectively) were grown in plastic pot with three (red, yellow and orange) anther donor (R0) F1minipaprika varieties. Regenerants were characterized for their plant and fruit characters as well as their fruit color and shape. The homozygosity of spontaneous diploid plants of each population was assessed using simple-sequence repeat (SSR) marker analysis. Haploid plants were characterized by reduced plant height, small leaves, short petiole and internode and small flower bud and all haploids showed the sterility and vice-versa in spontaneous diploid lines. The fruit biometrical traits exhibited greater variation within the spontaneous diploid plants and average value of quantitative traits is lower than standard varieties. MR-4 gave the highest yield (150.5 g) per plant followed by MY-6 (140.0 g) and MY-8 (130.5 g) and the lowest in MY-5 (31.5 g). Morphological marker such as fruit color further determinedthe microspore origin of androgenic diploids obtained in anther culture of ‘Vine sweet-red’. Of the fifteen spontaneous diploid plants, fourteen plants were identified as doubled haploids using microsatellite markers (SSR), and these homozygous lines are recommended to use in minipaprika breeding program.

Anther derived double haploids (DHs) from sweet pepper genotypes ('Special', 'Derby', 'Bossanova', 'Fiesta', 'Debora' and 'Minipaprika') were used to study the agronomic variation in 2006. Ninety-nine successful DHs regenerants (32 from 'Special', 25 from 'Derby', 23 from 'Bossanova', 10 from 'Fiesta', 6 from 'Debora' and 3 from 'Minipaprika') were transplanted at plastic house and studied on their agronomic characters. Variation in agronomic characters was observed within the DHs of each genotype. DHs obtained from 'Derby' and 'Fiesta' exhibited wide variation in fruit yield plant-1 whereas averaged fruit yield plant-1 was highest in 'Derby' (1608 g) and less variation was observed in DHs of 'Bossanova'. Based on the agronomic characters expressed in DHs population at this environment, SP55, SP56, SP60, and SP116 from 'Special', SP8, SP10, SP14, SP16, and SP34 from 'Derby', SP115, SP119, SP142, SP143, SP196, and SP199 from 'Bossanova', SP41, SP45, and SP114 from 'Fiesta', SP21 from 'Debora' and SP91 from 'Minipaprika' identified as elite inbred lines and these DH lines could be used for commercial hybrids production in sweet pepper. Genetic relationship among the selected inbred lines using molecular markers and their response to diseases are further recommended to study.

Anthers of sweet pepper F1 cultivar ‘Special’ were cultured on Dumas De Vaulx (C medium), supplemented with 0.1mgL-1 2, 4-D and 0.1 mg · L-1 kinetin with 3% sucrose, and 0.32% phytagel. The calluses obtained were further sub-cultured on Murashige and Skoog (MS) medium without growth regulators for regeneration. Regenerated plantlets were grown in plastic pots under plastic house and characterized their cytological and morphological characters in spring, 2008. Twenty percent plantlets were identified as haploid plants after chromosome and ploidy analysis. Haploid plants contained 12 chromosomes, high stomatal density with small stomatal length as compared to diploid plants. Stomatal length in haploids was 23.3% smaller than diploids. Haploid plants were characterized as small leaf and petiole size, poor vigor, thin stem and short plant height, short internodes and small flower buds, fruit size and fruit weight as compared to diploid plants and most of the haploid fruits were seedless. SP55, SP62, SP68, SP72 and SP77 are found high yielding double haploids with high total soluble content (8.6, 8.7, 9.2, 9.1 and 9.8 ºBrix, respectively) and desirable fruit shape, and recommended them to exploit as inbred lines for heterosis breeding.

Sweet pepper inbred lines (KNU1003, KNU1006, KNU1007, KNU1009, KNU1015, KNU1017 and KNU2006) developed at Kangwon National University (KNU) through conventional means, inbred lines (5AVS1, 5AVS2, 5AVS3, 5AVS5, 5AVS7 and 5AVS8) collected at Rural Development Administration (RDA) and inbred lines (SP12, SP27 and SP14) derived from anther culture were used as female parents and anther culture derived homozygous lines (SP9, SP10, SP14, SP24, SP25, SP27, SP30, SP32, SP34, SP38, SP43, SP45 and SP51) were used as male parents to produce F1 hybrids. A total of 37 F1 hybrids were evaluated for fruit yield and quality characters in summer season, 2007. Variation in fruit number, fruit weight, fruit yield per plant and fruit volume was observed among the F1 hybrids. Superiority on yield over standard/commercial varieties were differed among F1 hybrids. Hybrid 5AVS8 x SP45 exhibited highest heterosis over Special (16.5%) and Fiesta (24.7%). Fruit quality characters (fruit length, fruit width, pericarp thickness, total soluble solid, fruit shape and fruit color) were varied among the F1 hybrids. Fruit number, fruit weight and fruit volume per plant were correlated with fruit yield. Based on the standard heterosis expressed by the hybrids and quality characters evaluation, KNU1017 x SP27, 5AVS1 x SP43, 5AVS5 x SP27, 5AVS8 x SP45, SP12 x SP38 and SP27 x SP25 hybrids were found to be superior over commercial cultivars and are selected. Inbred lines of these hybrid combinations can be used to produce F1 hybrid seed for commercial production.