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.

There are many different types of cultivation in tomatoes for year-round production. One of them, semi-forcing cultivation is characterized by growing seedlings in winter season. If grafted seedlings are used in winter season that energy cost can be reduced, because they have tolerance to cold stress. This study was conducted to analyze the rootstock performance by measuring the growth, yield, and leaf-macronutrient content of cherry tomatoes grown in semi-forcing hydroponics. Three domestic rootstocks ‘HSF4’, ‘21LM’, ‘21A701’, and a control cultivar ‘B-blocking’ were grafted onto jujube-shaped cherry tomato (Lycopersicon esculentum L.) commercial cultivar ‘Nonari’. The total yield per plant with grafted cherry tomato ‘21A701’ was 3,387g, which was 11%, 22% and 24% higher than the yield with ‘B-blocking’, non-grafted one and ‘HSF4’. The stem diameter of ‘21A701’ was thick with 8.26mm, whereas non-grafted one was thin with 7.23mm at 160 days after transplanting. The flowering position of ‘21LM’ was 34% and 47% higher than the flowering position of ‘B-blocking’ and non-grafted one at 153 days after transplanting. The NO3-N concentration in petiole sap of ‘21LM’ was the highest with 1,746mg·L-1 and non-grafted one and ‘HSF4’ were the lowest with 1,252mg·L-1 and 1,245mg·L-1 at 167 days after transplanting. The results indicated that rootstock/scion combinations in cherry tomatoes can affect the plant growth, yield, and the concentration of different NO3-N in leaves at the late growth stage. Both ‘21A701’ and ‘21LM’ have vigorous root system, which influence the growth and yield increased.

Tomato (Solanum lycopersicum) is one of the most popular horticultural crops cultivated globally. Since the 1950s, the National Institute of Horticultural and Herbal Science (NIHHS) of Rural Development Administration (RDA) has been conducting research on developing Korean tomato cultivars. Recently, the objectives of breeding have been diversified according to the rapidly changing market trends. To meet such demands, various cultivars with distinct characteristics have been made: rootstock tomato, ornamental tomato, sweet cherry tomato, and virus resistant tomato. In 2022, a total of 20 cultivars were registered for variety protection in the Korea Seed and Variety Service (KSVS) and two cultivars with high temperature tolerance have been under field trials for application. In this paper, the breeding history and major characteristics of eight representative tomato cultivars are discussed. Since each tomato has its own valuable feature, they are expected to be used in diverse places from garden to farm.

‘파워가드’는 ‘6TS72S’ב07-9-47’ 교배조합에서 계통 분리 하여 선발하였다. 2007년 풋마름병 저항성 대목 품종인 ‘B 바리아(다끼이)’와 ‘B블로킹(다끼이)’ 간 교배를 실시하여 F1 조합을 작성하였고, 여기에 시듦병 저항성 유전자를 집적하기 위해 저항성 자원인 ‘07-9-47’과 다시 교배하였다. 매년 2세대씩 풋마름병 인공 접종을 실시하여 저항성 개체를 선발하였으며, 시듦병 저항성은 분자표지를 이용하여 확인하였다. 후대검 정으로 우수계통을 선발하고 2009년과 2010년 1년 2세대 진전으로 형질을 고정하였다. 2011년 풋마름병과 시듦병 등에 저항성을 보이며 균일성과 안정성이 확보된 F6세대의 고정계통을 최종적으로 육성하였고 이를 ‘파워가드’라고 명명하였다. ‘파워가드’는 풋마름병 뿐만 아니라 시듦병(I3), 고구마 뿌리혹 선충(Rex), 토마토 모자이크 바이러스(ToMV), 줄기 마름병 (Asc1), TYLCV(Ty3)에 복합내병성을 가지고 있다. ‘파워가드’의 생장형은 무한형이며 과형은 원형이며 평균과중 40 g 정도, 당도는 4.2 oBrix 정도이다.

‘티와이썬’은 농촌진흥청 국립원예특작과학원에서 육성한 토마토황화잎말림바이러스(Tomato yellow leaf curl virus, TYLCV) 저항성 품종이다. 모계로는 TYLCV에 저항성으로 알려진 자원 ‘08-9-59’를 도입, 세대진전하여 사용하였으며 부계로 사용한 ‘원예9002호’는 1997년 ‘트러스트’ x ‘모모타로 요쿠’ 교배조합에서 계통 분리하여 2002년까지 내병성 검정 및 계통 선발을 통해 육성하였다. 2010년 두 계통을 이용한 교배조합을 작성하였으며 2011년 내병성 분자마커 검정, 2012년 대만 AVRDC에서 담배가루이를 이용한 TYLCV 저항성 유묘검정을 실시하였다. 그 결과 TYLCV에 저항성이며 반신 위조병(Ve), 시듦병(I2, I3), 고구마뿌리혹선충(Rex), 세균성반점 병(Pto), 줄기마름병(Asc1), 토마토모자이크바이러스(ToMV)에 복합내병성으로 인정되어 ‘티와이썬’이라고 명명하였다. ‘티와 이썬’은 무한생장형에 과형은 원형이며 평균과중 240g 정도, 당도는 4.2°Brix 정도이다.