The Effect of Mixed Cultivation of Rice Varieties on the Plant Characteristics and the Occurrence of Blast under Various Fertilizer Levels

혼식(混植)한 몇가지 수도품종(水稻品種)의 생육(生育)과 병해발생(病害發生)

Three rice varietis, Dongjinbyeo, Daecheongbyeo and Chucheongbyeo, which are leading cultivars in the Chungnam area, were planted to determine their effects of mixture on the plant characteristics and the blast occurrence. The summary obtained is as follows; 1. The heading dates of each cultivars were not affected by the mixing culture. Only a day was delayed in heading date of Chucheongbyeo under commonly standard fertilizer level. 2. The effects of cultivar mixture on the plant height was high when low level of fertilizer were applied. Of the cultivar mixture, the mixing of Dongjinbyeo and Daecheongbyeo shoed 5.1% of plant height increase. The effects of mixture on the tillering number were apparent only under the standard fertilizer level. The mixture of Dongjinbyeo and Chucheongbyeo was effective in increasing the tillering number up to 5.7% over mean tillering number of each cultivars. 3. The stem height tended to increase as the fertilizer level increased and the effects of cultivar mixture on the stem height was high. The stem height of mixture of Dongjinbyeo and Daecheongbyeo was highest compared with other mixture cropping. On the contrary, the panicle length was shortened as the fertilizer level decreased and cultivars were mixed. Among the cultivar mixtures, the mixture of Dongjinbyeo and Daecheongbyeo showed the most effectives of increasing the panicle length. 4. The total dry weight of mixed and pure cultivars were compared. The mixture of two cultivars was effective in increasing the dry weight of rice upto 3.5% over the average of dry weight of each cultivars. When three cultivars were mixed, there were 8.5% of dry weight increase over not mixed cultivars. The effects of mixture on the dry weight were more apparent under standard fertilizer level. 5. The rates of Neck and Node and Branch Blast occurrence were reduced when cultivars were mixed, and their reduction rates were 11.7% and 14.0%, respectively. The occurrence of Blasts was also decreased under the lowest fertilizer level than the standard fertilizer level. The least Blast occurrence was obtained when Dongjinbyeo and Daecheongbyeo were mixed cropped. 6. Significantly high number of spikelets of per square meter was observed when Chucheongbyeo and Dongjinbyeo were mixed. However, the spikelets of panicle were the lowest when Chucheongbyeo and Dongjinbyeo were mixed. The number of panicles per square meter was increased as the fertilizer levels increased, while the number of spikelets per panicle increased as the fertilizer level decreased. 7. The effects of mixture on the maturing were apparent regardless of the fertilizer level. The 1000 grain weight was higher when lower level of fertilizer was applied. The effects of cultivar mixture on the 1000 grain weight were more apparent in the plots of Chucheongbyeo and Dongjinbyeo mixture and three cultivar mixture. 8. The grain yield increased when cultivars mixed. The increment under mixing cropping was 4.6% over mono cropping. The effects of cultivar mixture on the yield increase were more apparent under lower levels of fertilizer application. The highest yield increase was obtained when Chucheongbyeo and Daecheongbyeo were mixed, and the rate of yield increase was 6.8% over mono-cropping. 9. The grain yield was highly correlated with number of panicles per square meter and dry weight. There was not any significant relationships found among grain yield, spikelets of panicle and ripening percentage.

충남(忠南) 지역(地域) 일반계(一般系) 장려품종인 동진(東津)벼, 대청(大晴)벼, 추청(秋晴)벼 3품종(品種)의 혼식재배(混植栽培)가 병해(病害) 및 수량(收量)에 미치는 영향(影響)을 구명(究明)하기 위하여 1987년(年)에 충남대학(忠南大學) 농과대학(農科大學) 시험포(試驗圃)에서 수행(遂行)한 시험결과(試驗結果)를 요약(要約)하면 다음과 같다. 1. 혼식(混植)에 따른 품종(品種) 및 처리간(處理間) 출수기(出穗期) 변화(變化)는 차이(差異)가 없었고 추청(秋晴)벼 보비구(普肥區)에서만 1일(日) 지연(遲延)되었다. 2. 초장(草長)의 혼식효과(混植效果)는 소비구(少肥區)에서 높았으며 혼식조합별(混植組合別)로는 동진(東津)벼와 대청(大晴)벼 혼식조합구(混植組合區)에서 5.1%로 가장 높게 나타났고 경수(莖數)에서는 보비구(普肥區)에서 혼식효과(混植效果)가 나타났으며 혼식조합별(混植組合別)로는 추청(秋晴)벼와 동진(東津)벼의 혼식조합구(混植組合區)에서 단식구(單植區) 평균치(平均値)보다 5.7%가 증가(增加)하여 혼식효과(混植效果)가 가장 높았다. 3. 간장(稈長)은 시비량(施肥量)이 많을수록 혼식효과(混植效果)도 증가(增加)하였으며 동진(東津)벼와 대청(大晴)벼 혼식조합구(混植組合區)에서 간장(稈長)이 가장 길었으며 혼식효과(混植效果)도 높았다. 반대로 수장(穗長)은 시비량(施肥量)이 많을수록 감소(減少)하였으며 혼식효과(混植效果)도 떨어졌다. 혼식조합별(混植組合別)로는 동진(東津)벼와 대청(大晴)벼 혼식조합구(混植組合區)에서 수장(穗長)이 가장 길었으며, 혼식효과(混植效果)도 현저했다. 4. 성숙기(成熟期)의 지상부(地上部) 건물중(乾物重)은 단식구(單植區)에 비해 2품종(品種) 혼식구(混植區)에서 3.5%, 3품종(品種) 혼식구(混植區)에서 8.5% 증가(增加)하였으며 비료수준별(肥料水準別)로는 보비구(普肥區)에서 혼식효과(混植效果)가 현저했다. 5. 목도열병(稻熱病)과 지경(枝莖) 도열병(稻熱病)은 혼식구(混植區)에서 각각(各各) 11.7%, 14.0% 감소(減少)하였으며, 소비구(少肥區)보다는 보비구(普肥區)에서 혼식효과(混植效果)가 현저했으며, 혼식조합별(混植組合別)로는 동진(東津)벼와 대청(大晴)벼 혼식조합구(混植組合區)에서 도열병(稻熱病) 발생(發生)이 가장 적었다. 6. $m^2$당(當) 수수(穗數)는 추청(秋晴)벼와 동진(東津)벼 혼식조합구(混植組合區)에서 혼식효과(混植效果)가 가장 높았으나 수당(穗當) 영화수(穎花數)는 추청(秋晴)벼와 동진(東津)벼 혼식조합구(混植組合區)에서 가장 낮았다. 비료수준별(肥料水準別) 혼식효과(混植效果)는 $m^2$당(當) 수수(穗數)에서 비료수준(肥料水準)이 높을수록, 수당(穗當) 영화수(穎花數)는 비료수준(肥料水準)이 낮을수록 컸다. 7. 등숙율(登熟率)은 비료수준(肥料水準)에 관계(關係)없이 전(全) 혼식조합구(混植組合區)에서 혼식효과(混植效果)가 나타났으며, 1000립중(粒重)은 소비구(少肥區)에서 혼식조합간(混植組合間)에는 추청(秋晴)벼와 동진(東津)벼 혼식조합(混植組合)과 3품종(品種) 혼식조합구(混植組合區)에서 혼식효과(混植效果)가 높았다. 8. 수량(收量)은 단식구(單植區)보다 혼식구(混植區)에서 4.6% 증수(增收)되었으며 특히 소비구(少肥區)에서 증수(增收)가 현저했다. 혼식조합별(混植組合別)로는 추청(秋晴)벼와 동진(東津)벼 혼식조합구(混植組合區)에서 6.8% 증수(增收)되어 혼식효과(混植效果)가 가장 높았다. 9. 수량(收量)은 $m^2$당(當) 수수(穗數)와 건물중(乾物重)에 고도(高度)의 유의차(有意差)가 인정(認定)되었으며 수당(穗當) 영화수(穎花數)와 등숙율(登熟率)과는 유의차(有意差)가 인정(認定)되지 않았다.