elementary evaluation of corn germplasms for heat tension response and hybrid production
2004
barzegri, Mohammad | ghasmi, Jafar | Chogan, Rajab
In order to obtain the corn jermplasms with relative resistance to heat tensisons this research was estabilished by open polinated corn jermplasms recivied form internationl center for maize and wheat improvment (CIMMYT). Thirty _ two populiation of open polinated corn jermplasms were planted. Tn each populiation form emergence the morphological characterics and growth stages were noted by selection of 500 seedlings. Form silking and anthesis stage to physiological maturation of seed the charactericstics of each self _ polinated seed were noted After harvesting , 250 S0 cob were selected by cluster indices and period of silking , anthesis and growth sesason.. At the appearance intervals of crown flower generative organs and sink , and during growing period , 250 corn cobs of S0 were selected. In the second yearof the plan , in order to evaluation and screening selected S0 lines under heat stress , half of the every line’s seeds were stored in the storage and the other half were planted on two dates of 25 June as early planting and suitable planting dates , respectively. After taking notes and completing data tables , tolerance and sensitivity indices against heat , on early planting date , were determined for those lines of S0 which were relative tolerant. In the third year , the stored S0 seeds of selected lines , wich were relative tolerant against heat , were planted on the , selecting of lines was performed for enhancing gggenetic purity of S1 . At this stage , some 75 lines of S1 lines which were not sensitive to heat were selected.
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