Physio-Biochemical and Molecular Based Characterization and their Revaluation Under Heat Stress Conditions in Indian Wheat Cultivars (Triticum Aestivum L.)

Abstract

Climate models pred1ct greater mcreases 1n temperature in the future. H1gh temperature IS an environmental constra1nt limiting wheat productivity, tn India considerable acreage 1s affected by heat stress at seedling stage or adult plant stage or both. Genetic vanablhty among wheat cu1t1vars tor ab1hty to tolerate heat stress has been reported. W1th an object•ve to study the Phys1o- B1ochem•cal and molecular charactenzahon and the•r evaluation under heat stress COnd1t1ons •n lndtan wheat cultivars at different developmental stages an expenment with 52 genotypes was conducted at Ch1rodi farm and tn the laboratory of Ag 81otechnology Department Sardar Vallabhbhai Patel Un1verSJty of Agnculture & Technology , Meerut dunng Rabi season of Year 2011-12 & 2012-13 Heat stress were g•ven to wheat genotypes by delay SOWing of 30 and 50 days from normal date of sow1ng (25 November) so that the reproductive stage of flfst set (T1) and vegetative as well as reproductive stage of second set (T1) could expenence heat stress the artificial heat stress of 25/18"C, 30/18" and 35/18°C day/ntghl 1s prov1ded 1n growth chamber Yield and yield components were significantly affected under heat stress cond1hon S1gn•ficant reduction were v•s•ble 1n Morphological. Phys1olog•cal and 81ochem1cat parameters under T, and T2 heat stress cond1t1on in all the genotype, but out of 52 genotypes 23 genotypes were showed lower reduction. The results showed that heat stress treatment, genotypes and their interachon had sign1f1cant effects on all measured parameters Correlat,on analys1s showed that gra1n y1eld was pos1bvely correlated wrth membrane 11ab1ltty mdex. photosynthellc rate. chlorophyll content, canopy temperature depress1on. proline content total soluble sugar and starch content On exam1ne the gerrnonabon parameters under d•tferent temperature the heat tolerant genotype K 7903 and Ra1 3765 showed htgh gerrn1natoon eff1c1ency, surv•val rate and shoot & root length 1n companson to heat suscepbble genotypes PBW 343 and K 9006 under htgh temperature stress. 505-PAGE analySIS of graon prOielll extracts revealed the presence of one or more prote1ns 1n each genotype However, the heat stress s1gn1ficanlly affected the amount of prote1ns Heat stress reduced the amount of protems of high molecular we1ght. but 1ncreased the amount of prote1ns of low molecular weight Heat stress s.gmf1cantty altered the pattern of protein synthesis 1n wheat genotypes, and new bands undetectable under normal conditions were produced In add1t1on to the formation of new prote1n bands under heat stress condition. many heat &hoclt protems of 1ntermed.ate molecular wetght were synthesiZed 1n low amounts, as detected by electrophoregram scann1ng. Genet1c d1vers1ty IS eluctdated among 26 selected wheat genotypes through 40 SSR pnmers The pnmers produced htgh degree of polymorph1sm woth an average of 72.00 per oent The total of 40 pnmers amphf1ed 82 allels across the 26 genotypes, of them 75 fragment were polymorphic and showed 87% polymorphiC band On examine the cluster analysis the maximum s1m1lanty was obtauled between K9533 and K 9t07 They were 1n the same group with the slfndarity coeffioent 0 93 and Genotype K 9162 and C 306 were farthest or most d1verse genotype With a s1m1lanty coefficient of 0 60. Express1on analy'!' of rbc, psb and HSP 101 gene familieS under three set of temperature i e. 25°C. 30"C and 35 C clearly revealed that the genotype K7903 1nd RAJ 3765 (Heat tolerant) showed h1gh expression levels of rbc, psb and HSP 101 gene 1n companson to the genotype PBW 343 and K 9006 (Heat susceptible) under heat stress cond111on In Vitro callus 1nduct1on and plant regeneration was done With different growth regulator of whiCh, the best callus 1nduct1on was observed on. 2.4-0 (3 0 mgtl) while, the best shoot mitlahon was recorded on combination of SAP + K1nebc (2 5 mg/L each) and the best roolong was o NAA (4 0 mg!l).