Effects Of Different Sowing Date And Planting Density On Growth Of Winter Flax

The flax varieties of 1301-1349, used for test, are selected from different germplasm lines, whose sources mainly collected from different districts of Heilongjiang, Inner Mongolia, Ningxia Provinces. These lines have a rich diversity and broad genetic basis. Here we studied the genetic diversity of 49 flax samples and principal component analysis and cluster analysis.The varieties of 1348 and 1349 of second year, which performance good and stable, are selected for the test material. the effects on Growth, root distribution, photosynthetic characteristics, grain yield and quality of flax under different sowing date or density. The main results were shown as follows:The results showed that the coefficient of variation of agronomic traits between 10.57%-60.77% for 49 flax samples,the genetic diversity index of agronomic traits changes between 1.11-1.42; Correlation analysis of flax germplasm resources, the results were shown that there was a significant positive correlation between the yield and stem diameter, number of branches, number of capsules per plant, grains per plant, grain weight, branching starting point was, was negatively correlated with plant height. The cumulative contribution rate of the first three principal components of the 49 flax varieties reaches 71.23%. Variance contribution rate of the first principal component are the highest of all and they have dominant position, were 37.45%.The elite germplasm 1302,1349,1305,1348,1340 were screened from the first and second principal component. Our findings indicate that the 49 flax varieties were classified to 4 groups at Euclidean distance genetic level through cluster analys.Growth Characteristics of flax growth over time presents slow-fast-slow-fast-slow growth curve. Delayed sowing period the peak of the growth curve flax also will lag. It, Length of the flax, stem diameter, number of branches, number of leaves, leaf area, root length, root avgdiam, root surfarea, root volume, yield component factors increased as early sowing gradually. There were significantly negatively correlated between chlorophyll, leaf area index, net assimilation rate, photosynthetic duration and sowing dates. Early sowing increased grain yield,it help improve photosynthetic characteristics of flax and accumulation of photosynthetic products as yield formation stage. Under earlier Sowing conditions, yield maximum of 1348 and 1349 is 1878Kg/ hm2 and 2120Kg/hm2 respectively, an increase of 47.3%,49.15%,71.68%; 56.95%, 68.38%,78.67%, compared with the S2, S3 and S4. The grain yield yeild,the number of capsules per plant, number of seeds per plant, grain weight of 1348 and 1349 two varieties in descending order are October 12> October 22> November 2> November 12. The analysis showed that, the EE, unsaturated fatty acid and oleic acid & linoleic acid of 1348 and 1349 is 33.54%,90.17%,42.33% and 32.65%,90.24%,42.77% respectively with the early sowing, an increase of 27.60%,0.15%,2.34% and 31.45%,0.01%,0.54% compared with the S4. Explained above, early sowing can improve the grain yield and quality of flax oil.As the density increased plant height, root length, root surface area of flax showed an increasing trend. With increasing density stem diameter, number of leaves per plant, leaf area, root average diameter, total root volume of flax decrease. There were significantly positive correlation between photosynthetic duration,leaf area index and density, were significantly negatively correlated between chlorophyll, net assimilation rate, and density. The maximum density may play groups advantages and increase production. Under maximum density conditions, yield maximum of 1348 and 1349 is 1723Kg/hm2 and 1829Kg/hm2 respectively, an increase of 36.83%,64.31%,98.13% and 39.35%,62.11%,125.71%, compared with the D2, D3 and D4. Under conditions of maximum density of flax,the EE, unsaturated fatty acid and oleic acid & linoleic acid of 1348 and 1349 is 33.41%,85.12%,43.99% and 33.55%,90.05%,43.31% respectively, an increase of 18.68%,-5.44%,16.14% and 11.68%,-0.18%,1.87% compared with the high density of flax.Maximum density can improve the grain yield and the quality of flax oil within certain range.