Jong-Jin Hwang

Development of RAPD and SCAR markers linked to the Co gene conferring columnar growth habit in apple (Malus pumila Mill.)

Summary The columnar growth habit in apple is desirable for labour-saving cultivation, since columnar trees can be planted very close together with no staking and little pruning. Bulked segregant analysis and randomly amplified polymorphic DNA (RAPD) analysis were performed to identify DNA markers linked to the columnar growth habit (Co) using an F1 progeny of standard ‘Fuji’ (coco)× columnar ‘Tuscan’ (Coco). Of the 432 10-mer or 12-mer primers examined, only one clear and repeatable polymorphic product appeared to be linked to the Co gene. The RAPD marker, designated as WB82670, was located 1.8.cM from the Co locus, closer than markers reported previously for this gene. Based on the sequencing data of this product, two oligonucleotides of 28 bases containing the original 12-mer RAPD primer sequence (ATCCCACATTCC) were synthesized and used as sequence-specific primers for DNA amplification. All genotypes positive for WB82670 including ‘Tuscan’ gave a single product of 670 bp, while all WB82670-negative genotypes failed to generate any product. This sequence characterized amplified region marker, designated as SCB82670, linked to the Co gene will be useful to select for columnar growth habit at an early stage of apple breeding programmes.

`Joseong`, a New Early-Heading Forage Triticale Cultivar for Paddy Field of Double Cropping

`Joseong`, a winter forage triticale cultivar (X Triticosecale Wittmack), was developed by the breeding team at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2010. The cultivar `Joseong` was selected from the cross FAHAD_5/RHINO1R.1D 5+10 5D`5B`//FAHAD_5 by CIMMYT (Mexico) in 1992. Subsequent generations were handled in pedigree selection program at Mexico from 1993 to 1998, and a line `CTSS92Y-A-4Y-0M-5Y-0B` was selected for earliness and good agronomic characteristics. After preliminary and advance yield test in Korea for 2 years, the line designated as a line name of `Iksan26`. The `Iksan26` was subsequently evaluated for earliness and forage yield in 7 different locations such as Jeju, Iksan, Cheongwon, Yesan, Naju, Daegu, and Jinju from 2008 to 2010 and finally named as `Joseong`. The cultivar `Joseong` has characteristics of dark green leaf, yellow culm and spike, and large grain of yellowish brown color. The heading date of cultivar `Joseong` was April 24, which was 5 days earlier than that of check cultivar `Shinyoung`. It showed better tolerance or resistance to lodging, wet injury, powdery mildew, and leaf rust than those of the check cultivar `Shinyoung`. The average forage dry matter yield of cultivar `Joseong` at milk-ripe stage was 14.5 MT , which was lower than 16.5 MT of the check cultivar `Shinyoung`. The silage quality of `Joseong` (5.3%) was lower to the check cultivar `Shinyoung` (6.0%) in crude protein content, while was 2.1% superior to the check cultivar `Shinyoung` (61.9%) in TDN (total digestible nutrients). It showed 5.1 MT of grain yield, which was 40% higher than that of the check cultivar `Shinyoung` (3.65 MT ). This cultivar is recommended for fall sowing crop in the area where daily minimum mean temperatures are averaged higher than in January, and as a winter crop using whole crop forage before planting rice in around Korea.

Effect of Seeding Dates on Yield and Quality of Various Oat Cultivars for Year-Around Forage Production

Most oats are used for livestock feed in the world. This experiment was conducted at Iksan city of Korea from 2007 to 2008. The objective of this study was to select eminent oat (Avena sativa L.) cultivars with high-yielding and a quality for forage adaptable in each planting seasons. Experimental design was split-plot design with three replications. A split plot design was used with seeding date on the main plots and other treatments fully randomized in sub-plots. A factorial arrangement of treatments included three different ecotypes cultivars, winter type (Sanmhan, Donghan and Chohan), summer type (High-speed, Darkhorse, and Swan), and naked oats near to spring type (Daeyang, Choyang, and Sunyang) and twelve seeding dates (twice a month from March to November). Plant height, dry matter yield, and percent TDN was significantly affected by seeding dates, cultivars, and the interaction of cultivars seeding dates. There was a decrease in plant height, dry matter yield, and percent total digestible nutrients (TDN) as seeding was delayed from early March to late June and it also from early September to early November. The winter type oat cultivars such as Samhan, Donghan, and Chohan adapted to fall seeding and early summer harvest, while summer type cultivars such as High-speed, Darkhorse, and Swan showed high productivity either to summer seeding and mid-fall harvest or to spring seeding and early summer harvest. Naked type cultivars, Choyang and Daeyang, showed high forage yield by spring and summer seeding except for fall seeding because of cold damage. Summer type oat cultivars such as High-speed, Darkhorse, and Swan can supplement high forage production in spring. TDN yield showd the most at seeding in October 10 (780 kg ), followed at seeding in March 23 (627 kg ).

Change of Seed Yield, Germination Rate and Hard Seed Rate with Harvest Time in Hairy Vetch (Vicia villosa Roth)

This experiment was conducted to investigate an optimum harvest time for hairy vetch (HV) seed production. The seeds were harvested at 5 times, 35, 42, 48, 54, and 58 days after flowering (DAF) in 2009 and 2010. In 2011, 3 times of harvest, 39, 49, and 53 DAF were done at Suwon, middle part of Korea. HV plants were harvested and threshed by manually at each time. Seed yield, yield components, germination rate, hard seed rate, and viviparous germination rate were investigated. The highest seed yield represented 54 DAF in 2009, 42 DAF in 2010, and 49 DAF in 2011. When the triticale, HV support plant, comes to early lodging, the time of highest yield was delayed. 1,000-seed weight linearly increased from 35 DAF to 54 DAF. The later harvested seed showed a trend of increasing germination and hard seed ratio. However, viviparous germination had occurred because of in rainy season. In conclusion, it was presumed that an optimum harvest time for safe seed production in HV should be during 42 DAF ~ 54 DAF before the rainy season considering seed yield, 1,000-seed weight and germination.

Estimation of genetic distance and its predictability of F1 hybrid performance in barley

Heterotic performance of hybrids is dependent upon the amount of genetic variability among parents and combining ability of alleles at the loci associated with target traits. This study was carried out to determine if (1) pedigree-based genetic distance could explain molecular levels of genetic diversity, and (2) molecular marker-based genetic distance could predict the degree of hybrid performance in barley. The average value of Random Amplified Polymorphic DNA (RAPD)-based genetic similarity for all 58 genotypes was 0.641. Twenty-two hulless barley and eight malt barley varieties showed low levels of genetic diversity with higher similarity values than the average of all or of the hulled barley variety pool. Coefficients of parentage (COPs) computed for 1,653 pairs of 58 Korean barley varieties ranged from 0 to 0.984 with a mean of 0.048. Correlation between the genealogical and RAPD-based genetic similarity matrices was 0.256 (P < 0.01). Correlation values for the related and for all (related + unrelated) genotype pairs were almost similar to each other, indicating that the unrelated genotypes share a large portion of genomes alike in state, not identical by descent. RAPD-based genetic similarity estimates among parents were poorly correlated with their hybrid performance such as 1,000-grain weight (r = 0.34), biomass yield (r = −0.12), and grain yield (r = −0.04) for 11 genotype pairs of hulled barley. However, correlations between heterozygosity at marker loci and hybrid performance for biomass and grain yield slightly increased when two F1 hybrids were excluded in the analysis due to their low yield.

Abscission-related genes revealed by RNA-Seq analysis using self-abscising apple (Malus × domestica)

ABSTRACT The self-abscising characteristic of apple (Malus × domestica) fruit is a prominent labour-saving trait during cultivation. Early abscission up to 30 d after full bloom leaves only the central fruit in a cluster, while the four lateral fruit are abscised. A comparative analysis was conducted between the central and lateral pedicels in the self-abscising apple cultivar ‘Saika’ to identify the genes that trigger the abscission mechanism, as the destinies of the pedicels in a cluster are obvious. Transcriptome analysis was performed using RNA-Seq to compare expression profiles between the surviving central pedicel and the abscised lateral pedicels. A total of 797,647 expressed sequence tags were assembled into 65,876 contigs, which were annotated and analysed using Blast2GO. A total of 1,585 differentially expressed genes were identified in the central and lateral pedicels using NOISeq software. Differentially expressed genes were confirmed by quantitative real-time reverse-transcription polymerase chain reaction analysis, focussing on the genes associated with auxin signalling. Our data suggested that the IAA14/SLR gene is at least partly involved in the mechanism of abscission of the lateral pedicels.

A New Early-Heading and High-Yielding Winter Oat Cultivar for Whole Crop Forage, `Okhan`

`Okhan` (Avena sativa L.), an oat cultivar for winter use, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2011. It was derived from an original cross between `Early80`, exhibiting early heading, and `Maine PI-590` (CI 7518), exhibiting large-size grain, in 1995. Subsequent generations as well as cross-bred cultivars were handled in bulk, and pedigree selection programs took place at Suwon and Yeoncheon, respectively. A promising line, `SO95027-B-45-16-10-6-2-Y7-10`, was selected in 2004, and was designated `Gwiri74` after being selected from a yield trial for three years from 2005 to 2008. The breeding line `Gwiri74` was subsequently evaluated for earliness of heading and forage yield in four different locations, Yesan, Iksan, Kimjae, and Jeju, from 2009 to 2011, and was finally named as `Okhan`. Over 3 years, the heading date of `Okhan` was about 6 days earlier than that of the check cultivar `Samhan`, and their average forage dry matter yield harvested at the milk-ripe stage was 15.0 ton , compared with 14.1 ton of check cultivar. Cultivar `Okhan` was lower than the check cultivar `Samhan` in terms of the protein content (9.2% and 9.9%, respectively) and total digestible nutrients (58.5%, and 59.3%, respectively), while the TDN yield per ha was more than the check (8.70 and 8.36 kg, respectively). Fall sowing cropping of `Okhan` is recommended only in areas where average daily minimum mean temperatures in January are higher than , and it should not be cultivated in mountain areas, where frost damage is likely to occur.

A New High Grain Yielding Forage Rye Cultivar, “Seedgreen”

“Seedgreen” (Secale cereal L.), a new rye cultivar was developed by National Institute of Crop Science (NICS), RDA in 2013. It was developed from an open pollination from within 10 rye varieties or lines including “Chochun” in 1995. The line “SR95POP-S1-140-9-1-3-7-5-3” was selected for its excellent agronomic appearance, and was placed in yield trials for three years from 2008 to 2010. The new cultivar was designated “Homil50” and was placed in regional yield trials at the five locations around Korea from 2011 to 2013, during which time the name “Seedgreen” was given. This cultivar is an erect plant type and of a long size, with a dark-green leaf color, a yellowish-white colored, medium-diameter culm, and a brown-colored, medium-size grain. The heading and maturation dates of Seedgreen were April 22 and June 16, which were 3 days and 2 days earlier than that of “Gogu”, respectively. Seedgreen also showed better winter hardiness and a greater resistance to lodging and wet injury compared to those of the check cultivar. Over three years, the average dry matter yield of Seedgreen was 8.3 ton ha (fresh yield = 39.8 ton ha), which was harvested in late April and was lower than that of the check cultivar Gogu. The seed productivity of Seedgreen was approximately 4 ton ha, which was 16 % more than that of the check. Seedgreen was higher to than Gogu in term of protein content (10.5% and 9.7%, respectively), total digestible nutrients (TDN) (58.3% and 57%, respectively), and TDN yield ha (4.81 ton and 4.77 ton, respectively). This cultivar is recommended as a fall sowing crop in areas where the average daily minimum-mean temperatures are higher than -12°C in January, and as a winter crop for whole-crop forage before the planting of rice or green manure around Korea. (

Effects of Different Planting Dates on Growth and Yield Component in Two Ecotypes of Soybean at Paddy Field Condition in the Mid Part of Korea

This experiment was carried out to investigate the differences of the growth and yield characteristics at different planting dates in two soybean ecotypes from 2012 to 2013. Three summer types of soybean varieties, Seaol, Chamol, Hanol and three autumn types, Hwanggum, Taegwang, Daepung were planted 4 times from 1 May to 1 August in paddy field at the experimental field of National Institute of Crop Science in Suwon, Korea. Emergence rate was shown to difference among the varieties and the lowest planting at 29 June cause of the severe drought in 2012. The emergence period and days to flowering shortened as planting date delayed regardless of varieties. Emergence period more reduced in 2013 than in 2012 and days to flowering was more shortened in the summer types than in the autumn types. Stem height, number of main stem nodes, stem diameter were different among the summer types and the autumn types and reduced as planting date delayed. Number of main stem nodes and number of branch were different but no difference were observed in the stem height and stem diameter between 2012 and 2013. The number of pod per plant was the highest planting at 21 May and the lowest planting at 1 August and more in the autumn types than in the summer types. The number of seed per plant was the highest at planting 29 June and the lowest at planting 1 August and more in the autumn types than in the summer types and more in 2012 than in 2013. It was observed that one hundred seed weight was reduced rapidly planting at 1 August and heavier in the summer types than in the autumn types and heavier in 2013 than in 2012. Seed yield was the highest at planting 29 June and the lowest at planting 1 August, and 85kg/10a higher in the autumn types and 47kg/10a higher in 2012 than in the summer types and 2013, respectively.

A New Forage Oat Cultivar 'Taehan' for Early-heading and High-yielding of Double Cropping Cultivation in Paddy Field

‘Taehan’ (Avena sativa L.), a winter oat for forage use, was developed by the breeding team at the Department of Rice and Winter Cereal Crops, NICS, RDA in 2012. It was derived from a cross between ‘Malgwiri’ and ‘CI8015’. Subsequent generations were handled in bulk and pedigree selection programs at Suwon and Yeoncheon, respectively. After 2 years of preliminary and advanced yield tests, ‘SO00020B-YB-15-5-9-4-3’, designated as ‘Gwiri78’, were subsequently evaluated for earliness and forage yield during 3 years in four regions such as Yesan, Iksan-1 (Paddy), Iksan-2 (upland), and Jeju from 2010 to 2012, and finally named ‘Taehan’. Over 3 years, the heading date of ‘Taehan’ was about 6 days earlier than that of the check cultivar ‘Samhan’ (May 8 and May 14, respectively), and their average forage dry matter yield harvested at the milk-ripe stage was 14.5 tone ha, compared with 14.1 tone ha for the check cultivar. The cultivar ‘Taehan’ was lower than that of the check cultivar ‘Samhan’ in terms of protein content (6.3% and 7.7%, respectively) and total digestible nutrients (60.7%, and 62.1%, respectively). The TDN yield was more than that of the check cultivar (9.1 tone ha and 8.0 tone ha, respectively). Fall cropping of ‘Taehan’ is recommended only in areas where average daily minimum mean temperatures in January are >-6°C, and it should not be cultivated in mountainous areas, where frost damage is likely to occur. (