본 연구에서는 충남 연안에서 연안조망의 어획 특성을 파악하기 위하여, 2008년 3월부터 2009년 2월까지 매월 2∼4회 연안조망을 사용하여 어획조사를 실시하였다. 조사 해역은 동경 125도 50분∼126도 05분, 북위 36도 15분∼36도 25분의 해역이었고, 총 19목 63과 96종이 채집되었다. 그 중 어류가 54종, 갑각류가 27종, 복족류 및 이매패류가 9종, 그리고 두족류가 6종이었다. 생체량은 어류가 51.4 %로 가장 많았으며, 갑각류는 34.2 %를 차지하였다. 꽃새우는 7월~11월에 출현량이 많았고, 12월부터 5월까지는 적은 양이 출현하였다. 연안조망의 목표종인 꽃새우는 전체 어획물의 2.1 %로 낮은 채집 비율로 출현하였으며, 꽃새우 이외 어종의 부수적 어획물의 양적 비율이 높아, 꽃새우 어획이 부수어획으로 어획되는 종들의 수산자원에 미치는 영향이 클 것으로 판단된다.

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at 8℃, 13℃, 18℃, water temperature (12.8 to 24.2℃), and the best hatching temperature was 18℃. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

Japonica rice cultivars exhibit high susceptibility to bacterial blight(BB) disease due to genetic vulnerability in Korea. Korean japonica resistant rice cultivars mainly possess one of the genes, Xa1 or Xa3 for BB resistance. These resistance genes are becoming susceptible to K3a, resulting in serious rice yield reduction. This study was carried out to confirm the effect of xa13 gene pyramiding for developing of japonica rice cultivars resistant to BB pathogen breaking down Xa1 or Xa3. IRBB4 conferring Xa4 gene was resistant to K1(HB01013), K2(HB01014), K3(HB01015), and moderately resistant to K3a(HB01009). IRBB5 having xa5 gene was resistant to K1, K2, K3, and K3a. The recessive gene xa13 was resistant to K1 race but susceptible to K2, K3, and K3a. But Xa21 gene is susceptible to predominant K1 race but resistant to other races such as K2, K3, and K3a. Two genes Xa3 and xa13 were susceptible and Xa4 gene was moderate resistant to 24 isolates. xa5 and Xa21 genes were resistant to all isolates including K3a. When xa13 gene combined Xa4, xa5 and Xa21 genes, effect of xa13 gene pyramiding showed higher resistant reaction than that having singe gene out of Xa4, xa5, and Xa21. The order of resistance against 24 isolates breaking down Xa3 gene was IRBB55(xa13+Xa21) > IRBB53 (xa5+xa13) > IRBB51 (Xa4+xa13).