Male sterile line in onion is essential to the development of hybrid varieties. Onion male sterile line 'Wonye30005' was developed by Bioenergy Crop Research Center, NICS, RDA in South Korea in 2010. Lodging date of 'Wonye30005' is May 15th and it belongs to the early maturing type in Korea. We found the male sterile plants in ‘Hamasodachi’, early maturing open-pollinated variety, and the male-sterile plants were cross-pollinated with male fertile line, ‘M330’, the population of F1 showed 100% male sterility and the F1 plants were subsequently backcrossed for five generations. 'Wonye30005' was numbered as ‘MMS77’ in 2009 and the corresponding male parent is called MMSB77. 'Wonye30005' has round bulb shape (Bulb index, 97), cold resistance, and excellent storage quality and average bulb weight is 253g. Flowering date is May 25th and flower bud size is 84 mm in full bloom. The number and length of flower stalks per bulb are 4 and 134 cm, respectively. 'Wonye30005' has been filed in Korea Seed and Variety Service in 2010. Overall, 'Wonye30005' is promising male sterile line for early maturing type hybrid seed production and breeding program. (no 4673)

In order to produce the organic foods in accord with international standard, organic seeds should be used in organic farming. This study was conducted to establish the stable production of organic seed of waxy corn by examining the growing characteristics, seed yield, and the economy for seed production by organic farming. The optimal sowing timing for organic seed production of waxy corn hybrid was within 10 days of the 1st of May with yield of 88~90% of conventional seed production. The optimal planting density was 41,600 plants/ha (80×30 cm) for organic seed production of waxy corn. The weight of 100 seeds and seed productivity increased at the planting ratio of 2:1 mother plant:male plant. Growth and seed production were improved by removing male plant at 7~10 days after silking. Organic fertilizer (mixed oil cake) was applied at a rate of 4~6 Mg/ha before sowing. Black plastic mulching was used for weed control. In addition, sex pheromone trap and bio-control agents were used for safe pest control and low labour cost.

The pollen grain is a unique tricellular structure suitable for the delivery of the sperm cells to the ovule. All nutrients required for microspore and pollen cell growth are derived by passage through the anther locule and secretion by the tapetum lining. During later stages the tapetum degenerates but contributes to produce pigments, waxes, lipids and proteins which form the pollen coat and function in signaling between male (pollen) and female (pistil) tissues. The development of both normal pollen and tapetum is necessary for the fertilization processes in rice and would be exploited for the induction of male-sterility which is very useful to improve economic value of crops. We aredeveloping new approaches using a conditional male-sterility for the F1 hybrid seed production in rice. The conventional three parental systems for F1 hybrid seed production requirethe following three lines: male-sterile line, maintainer line, and restorer line. In this system, a critical requirement is to maintain the male-sterile inbred lines. Here we suggest molecular approaches, in which the engineered male-sterile plants are generated by regulating endogenous hormonal balance through the loss-of-function of genes. We can expect the male-sterility can be restored by exogenous applications of hormones such as gibberellin or jasmonic acid. Based on two parental systems, we will address the answer onfollowing question: how can we maintain a male-sterile line producing 100% male-sterile progenies without a maintainer? This work was supported by grants from Crop Functional Genomics Center of the 21C Frontier Program (CG1517), RepublicKorea.

옥수수 신품종 찰옥2호의 안정적인 F1 종자 생산에 적합한 채종 재배법을 구명하고자 1998-2000년 3년간 시험을 수행하였던 바 그 결과는 다음과 같다. 1. 찰옥2호의 KW7/KW3교배조합은 KW7의 수임능력 부족과 KW3의 화분비산거리가 짧아서 F1 종자 생산량이 적다. 2. 찰옥2호의 F1 종자 생산은 KW3/KW7 조합으로 하고 KW7에 비닐피복하여 모. 부본을 동시에 파종하며, 재식비율 4:1로 파종하는 것이 가장 효과적이었다. 3. 찰옥2호의 KW3/KW7 교배조합은 KW3의 부패립 발생이 문제가 된다. 따라서 종자의 품질저하 방지와 발아율을 고려하여 출사후 35일에 수확하는 것이 바람직하였다.

옥수수 변형단교잡종 채종재배에 있어서 웅주간파 ♂♀ 1 : 2, 2 : 4 등의 파종양식과 재식밀도가 종자친의 생육 및 채종량과 화분친의 웅수특성에 미치는 영향을 구명하고자 1983년 제천옥의 종자친 KS8/B68과 화분친 KS5를 공시하여 시험한 결과를 요약하면 다음과 같다. 1. 개화기 및 간장은 파종양식이나 재식밀도에 크게 영향을 받지 않았고 종자친의 착수고는 파종양식간에는 차이가 없었으나 재식밀도가 증가함에 따라 직선적으로 증가하였다. 2. 종자친의 100주당 수수는 10a당 종자친 3,500본에서는 파종양식간에 비슷하나 5,000본 이상에서는 2 : 4 재배보다 웅주간파나 1 : 2재배에서 많았으며 재식밀도 증가에 따라 파종양식에 관계없이 직선적으로 감소하였다. 수당입수는 파종양식간에는 차이가 없고 파종양식과 재식밀도의 상호작용도 유의하지 않았으나 재식밀도 증가에 따라 작아졌다. 100입중은 25g 내외로 처리간 차이가 없었다. 3. 화분친의 화분이 제한되지 않은 조건에서의 채종량은 웅주간파, 1 : 2재배, 2 : 4재배순으로 많은 경향이였고 10a당 종자 친 3,500본에서 5,000본으로 증가시킴에 따라 크게 증가하나 5,000본에서 6,500본으로 재식밀도 증가에 따른 채종량 증가는 크지 않았다. 4. 화분친의 웅수장과 웅수당 영화수는 1 : 2나 2 :4재배에 비하여 웅주간파 재배에서 작았고 재식밀도 증가에 따라 1 : 2 및 2 : 4재배에서는 크게 감소하였으나 2: 4재배에서는 유의하게 작아지지 않았다. 5. 변형단교잡종의 채종에는 1 : 2나 2 : 4재배의 10a당 종자친 5,000본 재식이 적합할 것으로 생각된다.