Bakanae disease, caused by various Fusarium species, poses a significant threat to global rice production, with its incidence increasing in major rice-producing regions. Currently, no rice varieties exhibit complete resistance to this disease. Enhancing resistance in rice cultivars could serve as a cost-effective and sustainable alternative to fungicide application. Developing resistant rice varieties may offer a practical solution to mitigate yield losses and reduce dependency on chemical treatments. ‘Jinokchal’ was derived from the cross between ‘Milyang299’, which harbors bakanae disease-resistant QTL qBK1. and ‘Baekokchal’ in 2014. A promising line, YR31624-5B-2, was then selected and designated as ‘Milyang366’ in 2019. The local adaptability test of ‘Milyang366’ was conducted at five locations from 2020 to 2022, and the cultivar was subsequently named ‘Jinokchal. ’ The heading date of ‘Jinokchal’ was August 13, classifying it as a medium-late maturing cultivar. The culm was 77 cm long and had 108 spikelets per panicle. The 1,000 grain-weight of brown rice is 22.7 g, which is heavier than that of ‘Sinseonchalbyeo’. This variety is resistant to blast, rice stripe virus, and bacterial blight, but susceptible to insect pests. The yield potential of ‘Jinokchal’ was approximately 497 kg/10a at the ordinary fertilizer level in the local adaptability test over three years. ‘Jinokchal’ is moderately resistant to bakanae disease and harbors the qBK1 gene derived from the tong-il type rice ‘Shingwang’ (Registration No. 8135).

In Asia, where climate change is increasing the damage caused by cold stress, it is crucial to cultivate varieties with enhanced cold tolerance. In this study, the Tongil variety ‘Hanareum2’ was crossed with the Japonica variety ‘Unkwang’ to improve plant growth ability at low temperatures during the seedling stage. This led to the development of 234 recombinant inbred line (RIL) populations, and a linkage map was constructed using 249 single nucleotide polymorphism (SNP) markers. The RIL populations were transplanted to the field one month earlier than the standard transplanting period, and plant height (PH), leaf number (LN), and dry weight (DW) were measured to identify quantitative trait loci (QTL) associated with plant growth ability at low temperatures during the seedling stage. QTLs related to cold tolerance, particularly those carrying the ‘Unkwang’ allele, were identified in the PH and DW traits. For PH, the QTLs qPH1, qPH5, and qPH8 were located on chromosomes 1, 5, and 8, respectively. Regarding DW, the QTLs qDW1, qDW8, and qDW9 were identified on chromosomes 1, 8, and 9. For the LN trait, qLN3 carrying the ‘Hanareum2’ allele was located on chromosome 3. If the identified QTLs are utilized, they can be incorporated into breeding programs for plant growth at low temperatures during the seedling stage.

To promote the expansion of rice consumption, we examined the nutritional components and qualities of five Tongil-type rice varieties. Regarding texture properties, ‘Dasan’ showed the highest viscosity at 0.43 kgf, whereas ‘Hanareum3’ displayed the lowest at 0.20 kgf. Regarding pasting properties, ‘Hanareum4’ exhibited the slowest aging speed of rice flour dough with a value of -42.34 RVU, and ‘Hanareum3’ had the slowest aging speed of cooked rice with a final viscosity of 258.62 RVU. Regarding proximate compositions, ‘Hanareum3’ had the highest crude ash content at 1.17 g/100 g, and ‘Hanareum2’ had the highest crude protein content at 8.39 g/100 g. Regarding amino acids, at 0.17–0.18%, ‘Dasan’ had a methionine content 0.13% lower than the other varieties. Regarding mineral contents, potassium, phosphorus, and magnesium contents were the highest in ‘Hanareum3’ at 263.08, 354.85, and 109.18 mg/100 g, respectively. ‘Dasan’ showed the highest contents of iron, manganese, and zinc, measured at 0.94, 2.17, and 1.43 mg/100 g, respectively. Of the 36 fatty acids measured, only 9 were confirmed. Myristic acid, linoleic acid, and alpha-linolenic acid were highest in ‘Hanareum3’ at 0.27, 9.91, and 0.48 mg/g, respectively. ‘Hanareum4’ had the highest levels of palmitic, stearic, and oleic acids, with contents of 6.69, 0.79, and 9.64 mg/g, respectively. Arachidic, eicosenoic, and lignoceric acids were detected at high levels in ‘Geumgang1,’ ‘Hanareum2,’ and ‘Dasan,’ with contents of 0.16, 0.13, and 0.3 mg/g, respectively.

Bakanae disease is caused by several species of Fusarium and imposes serious limitations to rice production worldwide. The incidence of this disease is increasing in the top rice-growing countries. No rice variety has been found to be completely resistant to this disease. Thus, higher resistance to the disease may be a cost saving solution preferable to the application of fungicides. ‘Anpyeong’ was derived from the cross between ‘YR24982-9-1’ and ‘Saeilmi’ in 2012 and selected as the promising line, ‘YR30389-B-2GH-103’; it was further selected and designated as ‘Milyang 313’ in 2016. The local adaptability test for ‘Milyang 313’ was conducted at five locations from 2016 to 2018 and the cultivar was named ‘Anpyeong’. The heading date for the medium-late maturing cultivar ‘Anpyeong’ was August 13. The ‘Anpyeong’ culm was 77 cm long and had 115 spikelets per panicle. The brown rice 1,000 grain-weight was 22.2 g, which is higher than that of ‘Nampyeong’. This variety is resistant to blast disease and rice stripe virus, but susceptible to bacterial blight and insect pest. The potential ‘Anpyeong’ yield was approximately 562 kg/10 a at ordinary fertilizer level in the local adaptability test and for three years. ‘Anpyeong’ harboring the qBK1 gene derived from a tongil type rice ‘Shingwang’ is moderately resistant to bakanae disease (Registration No. 8135).

A total of 285 Korean rice cultivars were used for amylose content and genetic analyses using KASP markers related to the amylose content. We used three polymorphic KASP markers targeting the Waxy (Wx) gene and compared the genotyping efficiency with previously reported molecular markers. The rice cultivars were raised in Miryang, Korea, for one period. Genetic analysis of the rice cultivars revealed that the three KASP markers on the Wx gene were functional for genomic selection of SNPs related to amylose content variation. Therefore, the three KASP markers targeting different Wx alleles can be used for genomic selection. In addition, KASP markers were more efficient than previously reported molecular markers that target the same alleles. These findings can be beneficial for the breeding and genomic selection of high-quality rice in Korea.

Bakanae disease is an important fungal disease caused by Gibberella fujikuroi. Incidence of rice bakanae disease creates serious problems in the foremost rice producing countries, affecting more or less all known rice cultivars. Breeding rice cultivars resistant to bakanae disease will thus be a cost-effective alternative to the application of fungicides. ‘MY299BK’ was derived from a cross between YR24982-9-1 and ‘Ilpum’ in 2008. A promising line, YR28297-1-38-1-1, was selected from among the progeny and designated ‘Milyang299’ in 2013. The local adaptability test of ‘Milyang299’ was carried out at five locations from 2014 to 2016 and named ‘MY299BK’. The heading date of ‘MY299BK’ was Aug. 15, typical for a medium-late maturing cultivar. Its culm was 71 cm long, there were 114 spikelets per panicle, and 1,000 grain-weight of brown rice was 23.4 g; these parameters were similar to those of ‘Nampyeong’. ‘MY299BK’ cultivar was resistant to blast and rice stripe virus, but susceptible to bacterial blight and insect pests. Its yield potential was about 566 kg/10 a at ordinary fertilizer level in a three-year-long local adaptability test. ‘MY299BK’ resistance to bakanae is conferred by the qBK1 gene derived from a tong-il type rice ‘Shingwang’ (Registration No. 7651).

Rice stripe virus (RSV) is one of the major constraints in rice production which is transmitted by the small brown plant hopper, Laodelphax striatellus. Identifying new resistance genes from diverse sources is important for rice breeding programs to enhance the resistance level and/or to overcome the breakdown of resistance genes. This study was conducted to identify novel sources of resistance against RSV. We used five RSV resistant varieties that do not harbor Stv-bⁱ. The presence of known genes for RSV resistance was identified using the InDel7 marker for Stv-bⁱ, two Indel (Sid primer set) markers for Stv-b, and DNA sequence analysis for OsSOT1. We revealed that two varieties, 02428 (IT236925) and Tung Ting Wan Hien 1, are novel RSV resistance sources.

Rice tungro disease is a serious threat to rice production in South and Southeast Asian countries. Rice production in these countries has been intensified, often through continuous cultivation of rice. We conducted a screen of the resistance to tungro virus disease in Korean japonica rice. Dongjin, Hwaseong, and Sangju were varieties resistant to Rice tungro spherical virus (RTSV) but susceptible to Rice tungro bacilliform virus (RTBV). RTSV-resistant variety Sangju was crossed with RTSV-susceptible variety Unkwang to conduct a genetic analysis for RTSV resistance originating from Sangju. Evaluation of 201 F2 plants from the cross between Unkwang and Sangju showed that there were 85 plants showing resistance, and that 116 plants were susceptible, indicating a ratio fitting a 7:9 ratio ratio (χ² = 0.54; p = 0.46). Thus, the resistance to RTSV in Sangju might be controlled by two recessive genes. This result indicates that Sangju might serve as a useful genetic source for diversification of RTSV resistance and stabilization of resistance through gene pyramiding.