Identify the effective traits for the selection of quinoa (Chenopodium quinoa Willd.) lines in spring cultivation under saline condition

Quinoa is an allotraploid crop, C3 (2n = 4x = 36) from the Amaranthaceae family and is of great global interest due to its high nutritional value. Quinoa is native to South America and has been cultivated in these areas for 5,000 years. Quinoa has an average of 16% protein and free gluten. Climate change and salinity and drought stress have led farmers to turn to new plants to maintain production in these conditions. Quinoa has a high genetic diversity in terms of tolerance to salinity stress, maturity time and other agricultural traits. The project aims to select promising quinoa lines in saline conditions in spring cultivation.

In order to select quinoa lines in spring cropping under saline conditions, 13 lines with different maturity periods in 3 lines with 5 meter lines at Sadough salinity research farm of Yazd based on complete randomized block design with three repetitions with 14 dS/m saline water in 2016. Initially, the seeds were planted in a seedling tray and after 21 days, transferred to the farm on March 9. Twice spraying was performed to control the spodoptera larvae during the floral initiation stage. The three stages of urea fertilizer were carried out at first, at the beginning of the floral initiation and anthesis stages. The phenological steps were recorded and the sodium percent, the potassium percent in the leaves and the ratio of potassium to sodium in the anthesis stage and finally the plant height, the thousand kernel weight (TKW), biomass and seed yield were measured. Data were analyzed with SAS software and cluster analysis, correlation analysis and principle component analysis were performed by Statographic software.

The results of analysis of variance showed that in terms of all the measured traits the difference among the lines was significant. The mean comparison showed that Line 6 had the highest seed yield (1422 Kg ha-1) with a significant difference, and then Lines 7, 10 and 11 had high seed yield. TKW of lines 6 and 11 with a rate of 1.9 and 1.8 g had a significant difference with other lines. The correlation relationship between traits showed that seed yield had significant correlation with TKW and days to maturity. In the cluster analysis, lines 11 and 6 in the early group had the highest seed yield and TKW. The high temperature during the period of grain filling in spring cultivation reduced the seed yield and TKW and lines 15 and 16 because of high temperature and long day did not start flowering. The evaluation of temperature in the grain filling period showed that with increasing each degree of the average temperature and maximum temperature seed yield decreased by 118 and 184 Kg ha-1 and TKW decreased by 0.2 and 0.27 g, respectively. Principle component analysis showed that the three components had the largest share in variance, and in the first, second and third components, the TKW, the ratio of potassium to sodium and the percentage of potassium in the positive direction and day to maturity, day flowering and plant height with seed yield had the largest share in the negative direction, respectively. Lines 11, 6 and 10 had the highest share in the total of three components in the direction of yield.

Quinoa had a high ability to absorb potassium under salinity stress, and the heat of the end of the season reduced the yield and TKW in the late mature genotypes. The most important traits for selection in spring cropping under salinity stress were grain yield, early maturity, TKW and potassium-to-sodium discrimination trait, and finally lines 11 and 6 were selected for further study in spring cropping. Among the studied traits, TKW, day to maturity, and the percentage of sodium and potassium ions were effective in line selection.