Abstract:
University of Phayao Maize Improvement (UPMI) project has aimed to develop inbred lines and their F, hybrids of field corn having hight yield potential and adaptation for highland. From selfing and selection of eighty-nine lines, twelve lines were selected having good agronomic characters. For example, there were plant and root vigor scoring 5. The percentage of tasseling and silking were averaged about 58 days. In addition, stem and rood lodging were scored about 4. Plant and ear aspects were moderately score about 3. Then F, hybrids were made and were planted for yield trial in late rainy season 2014. The results showed that UPFC14 was the highest grain yield about while 2,422 kg/rai. Check variety, P4199 was about 2,124 kg/rai. In the early rainy season of 2015, the best five hybrids were chosen and sowed comparing with check variety. From yield trial, UPFC11 had yielding about 1,804 kg/rai and P4546 (check) having grain yield about 1,966 kg/rai. Then, crossing were made for two methods, diallel cross and topcross. Evaluating yield trial in dry season of 2016, UPF04 x Ki48 showed the highest grain yield about 2,207 kg/rai higher than DK8868 (check) was about 2,013 kg/rai. Furthermore, UPF22 and UPF07 were the best general combining ability of topcross and diallel cross, respectively. Moreover, the highest specific combining ability were the cross of UPF02 x Ki60 and UPF07 x UPF02 from the topcross and diallel cross methods, repectively.