|Title:||Bt Cotton: A Cost-Effective & Green Technology for the Cotton Industry|
|Researchers:||E. C. Riñen, M.C. Damo, E.C. Cabigan, M.Q. Pascua, N.D. Cacayorin, G. A. Rosario, M.E. Barroga, C.A. Dacanay, V.B. Cosico, and E.D. Orpia, Jr.|
Five transgenic cotton hybrids with the fused Bt genes, cry1Ab and cry1Ac (GFM Cry 1A) were evaluated in Luzon and Mindanao for possible commercialization. The Luzon evaluation was done in Alcala, Pangasinan and Batac City, Ilocos Norte for two cropping seasons: CY 2012-2013 and CY 2014-2015. With one non-Bt local variety UPL-C2, the five cotton hybrids were NECH 2, NECH 14, NECH 21, NECH 25 and NECH 34.
The field test showed a remarkable effectiveness of all the six Bt cotton hybrids in controlling the cotton bollworm (Helicoverpa armigera Hubner). Their bioefficacy was supported by low larval counts at critical stages, high bollworm mortality and minimal damages in squares and bolls, resulting to high boll retention and productivity.
The Bt cotton hybrids were prolific; all had comparable size of bolls to the non- Bt local variety, both hybrids and the local variety matured at the same time, but all hybrids except one, significantly produced more seedcotton than UPL-C2. UPL-C2 had the highest lint recovery and comparable only to NECH 21, while the others had lower lint recoveries that ranged from 34.62 to 38 percent. Nevertheless, all the hybrids had significantly higher lint yield than UPL-C2 because of the higher seedcotton yield of the former. The hybrids generally had better fiber than UPL-C2. NECH 25 stood out as having very strong, long and very fine fibers. The rest had strong fibers, except one, NECH 21, which was similar to UPL-C2 having average strength. All the hybrids except NECH 21 had long fiber. NECH 21 had medium-long fiber similar to UPL-C2. Four hybrids had fine fiber while UPL-C2 had average fineness.
The cotton bollworm moth did not discriminate between the Bt cotton hybrids and the non-Bt cotton variety in its oviposition. The moth laid its egg in comparable number in both types of cotton and in different plant parts. However, the number of mortality from hatched larvae in the two types of cotton was markedly significant. Larval mortality in the Bt cotton hybrids ranged from 85.7 to 91.2 percent compared to zero mortality or 100 percent survival in the non-Bt local variety.