Enhanced boll production in transgenic cotton lines in a field study
The apparent increase in heat tolerance of reproductive tissues in AtHSP101 transgenic cotton lines was further evaluated under field heat-stress conditions in the field in Maricopa. Fig 13 shows the maximum and minimum air temperatures in Maricopa, Arizona during the peak of boll production in the growing season. Temperatures over 38°C were common throughout the flowering and boll development period. Table 3 provides the average data on the total number of bolls per plant, open bolls per plant, seed numbers per open boll, and closed bolls per plant for twenty plants for each of null line 39 and transgenic line 40 at the time of harvesting on September 27. The transgenic line 40 produced an average of 35% more bolls than the null 39 line. No significant difference in the number of open bolls or seeds per open boll was observed. The difference in total boll numbers was attributed to an increase in the number of closed bolls per plant. Overall, field results further demonstrated the enhancement of reproductive tissue heat tolerances in HSP101 transgenic cotton plants.