Yield trial of F2 population obtained from varietal crosses between sweet corn and thein corn varieties | การทดสอบผลผลิตประชากรลูกผสมชั่วที่ 2 ที่ได้จากการผสมระหว่างพันธุ์ข้าวโพดหวานกับข้าวโพดเทียน

Germplasm is an important factor to contribute to plant breeding successes. Thein corn varieties in Thailand are specific in each location. The seed collected from small size population, that a cause of narrow genetic base. The objective of this research was to find the potential of sweet corn varieties to improve agronomic traits of thein corn having adaptability on diverse environments. Forty-eight of F1 were obtained by varietal crosses between 12 sweet corn and 4 thein corn varieties as Line x Tester analysis. The F1 varietal crosses were selfed to produce F2 varietal cross populations about 30 ears/cross. Characteristic of F2 seeds in each ear segregated to normal and wrinkle. The normal seeds in each F2 varietal cross were tested by potassium iodide. Only seeds showed red brown endosperm were selected and bulked in each cross. The 48 F2 varietal cross populations were grown with 4 check varieties using randomized complete block design with 3 replications. The result showed that F2 varietal cross populations were significantly different for all studied traits. Yield based on ear number, ear size, plant height, ear height, and flowering date of segregating population were higher than check varieties. For yield based on ear per area, F2 varietal cross populations had ear number less than TLK1, a prolific check variety. HYB49 and WSS are sweet corn parents which produce high yield of F2 varietal cross populations, better than other sweet corn parents. However, interaction between sweet corn and thein corn parents exhibited significant difference (P<0.05) for marketable yield. There were 4 interesting F2 varietal cross populations namely AGR/TLK1, ATS2/TLK1, WSS/TLK1 and ATS5/TBK. Their SCA were 0.35, 0.35, 0.25 and 0.25 ear/plant, respectively and produced yield based on marketable ear number above 11000 ears/rai and gave marketable unhusked ear weight above 1.1 ton/rai. Their agronomic traits were good but ear size, especially ear diameter and number of seed rows exceeded thein corn standard. For population improvement or inbred extraction, breeder should focused on prolific ear, ear size and shape during make a selection.