Combining abilities and heterosis of five maize cultivars for industrial baby corn (Zea mays L.)

The maize experiments were carried out at Khon Kaen University on Yasothon soil series during 1990 in the pursuit of better combining abilities and heterosis of five maize cultivars as to obtain new varieties for industrial "baby corns" both fresh and canned food products. The five maize cultivars being used were: KKU1, R1-KKU SRC6, BC1 DMR, SW2, and CMB. These maize varieties were used as parental materials. Both direct and reciprocal crosses produced 20 off-springs and the seeds of both direct and reciprocal crosses and parents were sown for progeny test and this was carried out for two seasons i.e. drys and wet seasons. Both experiments were laid out in a Randomized Complete Block Design with four replications. The data obtained were statistically analyzed with the use of cross diallel-analysis II and analysis III. The results showed that there were some highly significant effects due to sowing season on harvesting age, number of cobs/rai, cob fresh weights/rai and also some interactions between season and crosses on harvesting age, and season and ratio between cob fresh weights and baby corn fresh weights. Dry season hastened harvesting age of baby corns but a delay with wet season. The results on reciprocal analysis revealed that significant effects were found with number of cobs/plant, cob fresh weights/rai, baby corn fresh weights/rai, standard weights of baby corns/rai, and out standard weights of baby corns/rai (1 ha = 6.25 rai). The results of reciprocal crosses revealed that there were significant effects on number of cobs/plant, cob fresh weights/rai, baby corn fresh weights/rai, standard baby corns/rai, and out-standard baby corns/rai due to maternal effect. With diallel analysis, an excellent general combining abilities was found with harvesting age on direct crosses and number of cobs/plant of reciprocal off-springs but only found with dry season. Gene expression was not freely independent of season. SW2 variety has a short harvesting age while KKU1, and BC1 DMR (1x3) possessed highly significant effects on GCA and SCA. The best variety for open-pollinated fertilization was BC1 DMR. There was a highly significant correlation between cob fresh weights and baby corn fresh weights and did between cob fresh weights and out-standard cob fresh weights.