Effects Of Brassinolide And Sowing Date On Seed Potato Vigor,plant Growth And Yield In Alpine Mountains

Potato is the leading industry in the alpine mountainous area of Sichuan province.It is an important way to realize the green and efficient development of the potato industry in this region to enhance the vitality of potato seed,enhance the resistance of potato and improve the cultivation technology with nutrient management as the core by selecting suitable sowing date and chemical control treatment.Therefore,in this study,the high-yield and high-quality main cultivars’ Mila ’and’ Chuanliangpotato No.10 ’were used as experimental materials.In 2021,2,4-table brassinolide(BR,a cis-trans isomer of BR)was used as treatment agents,and the seeds were immersed at 0,0.05 and 0.10 mg/L BR concentrations,respectively,for field tests.In 2022,a two-factor test was used to set 0,0.05,0.10 mg/L BR concentrations,3 mg/L BRz(BR biosynthesis inhibitor),3 mg/L bikinin(BIN2 inhibitor(BR negative regulator)),respectively.And February 20(early broadcast),March 12(regular broadcast),April 2(late broadcast)three days.To study the effects of BR and sowing date on potato seed vigor,plant morphology,nutrient uptake and dry matter accumulation in various organs,yield formation and their relationship.The main results are as follows:1.Effect of BR seed soaking and sowing date on seed potato vigorDifferent concentration BR soaking treatment and different sowing date significantly affected potato seed activity.The activity of seed potato was higher than that of early/late sowing,and the combination of conventional sowing and early sowing with BR0.05mg/L and0.1mg/L could significantly improve seed potato activity,promote seedling main stem number,plant height,stem diameter,total root length,total root volume,and increase leaf SPAD value and leaf area.The results showed that suitable BR concentration treatment and sowing date could improve the vitality of seed potato.2.Effect of BR immersion and sowing date on potato plant growthSowing date had significant effects on plant height,stem diameter,dry matter accumulation,chlorophyll content and root activity of potato during the whole growth period,and each index value showed that early sowing/conventional sowing > late sowing.Plant height and stem diameter reached the highest level at flowering stage.The optimal BR concentration of different varieties was different.The optimal BR concentration of ’Mila’ was0.05 mg /L,and that of ’Chuanliang No.10’ was 0.1mg /L.At the same time,0.05 mg/L BR treatment could significantly promote root elongation,root absorption area expansion,root diameter and volume expansion,and increase the number of stolons.3.Effects of BR immersion and sowing date on dry matter accumulation and accumulation of N,P and K in potato organsDry matter accumulation and N,P and K absorption of potato organs were significantly affected by the interaction between different BR soaking treatments and sowing dates.The dynamic changes of dry matter accumulation of whole plant and accumulation of N,P and K in each organ during sowing were as follows: early sowing/regular sowing > late sowing.Early sowing combined with 0.1mg/L BR treatment effectively coordinated the growth of aboveground stems and leaves with underground roots and tubers,thereby improving the whole plant dry matter accumulation from seedling stage to flowering stage and increasing the accumulation of N,P and K of tubers at harvest.4.Effect of BR immersion and sowing date on potato yield formationIn the conventional sowing period,BR treatment could significantly increase the weight per plant,the number of tubers and the percentage of large tubers,and thus significantly increase the yield.’Mila’ had the best performance at 0.05 mg/L BR treatment,and’Chuanliangdou 10’ had the best performance at 0.1 mg/L BR treatment.The correlation analysis of different BR treatments,sowing date and potato yield showed that early sowing with 0.1mg /L BR treatment had the best performance,which could alleviate the effects of cold injury on seedling growth,make full use of light and temperature resources,and increase the number of potato producing per plant,yield per plant and total yield of ’Mila’ and’Chuanliangpotato 10’.Compared with CK,the increase was 35% and 26%.The best performance of late broadcast ’Mila’ was bikinin treatment,which increased by 20%,and BR treatment had no significant difference in the output of ’Chuanliang No.10’.The above research results provide experimental basis for guiding the high yield,high quality and high efficiency of potato production in the alpine mountains and have important significance for promoting the resistance and increase of potato production.