Soybean has a high protein content in both its hay and seed. Studies have shown that the mixed cropping of corn and soybean improved forage yield and quality. The
objective
of this study was to select soybean germplasm suitable for mixed cropping with corn on the same row to produce better forage yield and quality. Eleven soybean lines selected from previous evaluations were used in this study. Soybeans were planted with corn on the same row at 10 cm intervals. The planting rate in hills was one corn plant and three soybean plants. The fertilization and time of forage harvest were based on the recommendations for forage corn production. The results showed that in corn–soybean mixed cropping, the forage yield increased by about 19%, the silage protein content increased by 1%–2%, the percentage of acid detergent fibers and neutral detergent fibers decreased, the total digestible nutrients increased, and the acetic acid content decreased. Therefore, the selected soybean lines were suitable for mixed cropping with corn to produce high quality forage and/or as breeding material for the development of forage soybean varieties. Based on this study, we suggest that the agronomic traits of soybean needed for mixed cropping with corn on the same row for forage are as follows: soybean should 1) have the ability to grow well under the corn canopy, 2) have lodging tolerance for ease of mechanical forage harvest, 3) develop to the full pod stage at the time of harvest for increased protein content, and 4) have no adverse effects on corn growth to maintain a high forage yield.

In order to select pollinizer varieties of high fruit qualities with large sized and high soluble solid contents, ‘Nishimurawase’ was crossed with ‘Johongsi’ at the Pear Research Institute, National Institute of Horticultural & Herbal Science in 2000. Among these crossed seedlings, ‘00-16-121’ was selected primarily in 2007, and it was finally selected since it was worthy of not only a pollinizer but also ripen and dried persimmon and named ‘Partner’ in 2009. ‘Partner’ shows intermediate in growth habit and semi-spreading tree shape. It has plenty of male flowers and rich pollen amount with about 380 mg per one hundred flowers. The average optimum harvest time of ‘Partner’ was 144 days after full bloom and it matured around one week earlier than ‘Zenzimaru’ and three weeks later than ‘Nishimurawase’. The fruit is elliptic in shape and orange in skin color. Average fruit weight was 224 g, and soluble solids content was 18.8°Brix.

‘Cheongpoongbora’, a winter hairy vetch variety (Vicia villosa Roth) for green manure use, was developed from the National Institute of Crop Science (NICS) in 2009. Among the genetic resourced collected in Daegu, early flowering, strongly resistant to cold, and high yield in green manure, was selected by pedigree selection method. Over the two years from 2008 to 2009, regional yield trial test was conducted with the line in four regions: Suwon, Iksan, Milyang, and Yeongdeok. As a result, in December 2009, it was named ‘Cheongpoongbora’ as a new variety. ‘Cheongpoongbora’ features medium green color leaves, medium density hair, and black seed coat. Flowering season for the variety was on April 29 on average across the nation, 11 days earlier than the check variety ‘Welta’. Also, it was more resistant to cold than ‘Welta’. The dry matter yield was average 5.20 tons per ha, 5.9% higher than ‘Welta’ (4.92 tons), the nitrogen yield was average 166 kg per ha, 6.4% higher than ‘Welta’ (156 kg). ‘Cheongpoongbora’ can be cultivated in any national regions which have the daily minimum mean temperature of over -15°C in January.