Screening And Utilization Of Cold Resistant Germplasm Resources In Maize

To screen stronger cold resistance and high-yielding maize combinations which are suitable to early sow in Spring and can resist low temperature damage in Autumn, screening of cold resistance was conducted by cold stress experiment and stage sowing experiment with12inbred lines of maize, H252, Lian848, Lian87, G54-2, G54-1, Xin3,543, S543, H37-2,1108, Qi319and14-3, as materials. So,7inbred lines with stronger cold resistance were screened out. And then21cross combinations was gained by crossed between each two inbred lines with stronger cold resistance. And then cold stress experiment and stage sowing experiment were conducted with21cross combinations and Linao No.l were materials to compare their cold resistance by subordinate function analysis based on agronomic traits, yield and physiological indicators. The main results were as follows:(1) In this experiment, seedling rates of all inbred lines in field were inconsistent with the integrated values of physiological indicators under low temperature stress, and variations of different physiological indicators of the same inbred were not the same. By comprehensive evaluation, the cold resistance of12inbred lines showed the trend of H252> Lian87> Qi319> G54-2> G54-1> I108> Lian848>14-3> S543> H37-2>543> Xin3. Therefore, the former7inbred lines were selected to be materials to hybridize and21combinations were gained for cold-resistance research.(2) With the delay of Autumn sowing, the growth duration of all hybrid combinations was prolonged, the plant height of Lian848x Lian87and Lian848xQi319showed increase trend, plant height of G54-2x H252, G54-2×I108, G54-1x H252and Qi319x G54-2showed significant decrease trend, plant height of others changed unclearly, and ear height and leaf area of all combinations changed unclearly.(3) Compared panicle traits and yield traits of22hybrid combinations under two sowing date, ear length and bald tip length of July25treatment were longer than those of August10treatment, while ear rows, row grains and ear diameter were affected unclearly by sowing date. With delay of sowing, ear weight, grain weight per ear, yield per area were decreased significantly, while difference in panicle traits and yield traits of Lian848x Qi319was unclear, which was less affected by low temperature.(4) Comparison on yield of22combinations in same sowing date showed that:in July25treatment, yield of Lian87x Qi319was the highest, the next was Lian848×Qi319,675.32kg/667m2. In August10treatment, yield of Lian848×Qi319was the highest,608.58kg/667m2. In22combinations, decline in yield of Lian848x Qi319was smallest, so Lian848x Qi319affected by low temperature unclearly, which was suitable to plant as Autumn maize and sow before August10.(5) In the cold stress experiment, the integrated value of Lian848×Qi319was next to Lian848x1108, which showed that Lian848x Qi319had stronger cold resistance and it was suitable for early sowing in Spring.