000 04547nam a22004577a 4500
001 G64337
003 MX-TxCIM
005 20240828180714.0
008 121211s1997|f| mx |p||0|| | e eng d
020 _a968-6923-91-8
040 _aMX-TxCIM
041 _aeng
072 0 _aF30
072 0 _aH20
090 _aLook under series title
245 0 0 _aUsing canopy temperature depression to select for yield potential of wheat in heat stressed environments
260 _aMexico :
_bCIMMYT,
_c1997.
300 _a46 pages
340 _aPrinted Computer File
490 _aCIMMYT Wheat Special Report (WPSR) ;
_v42
_x0187-7787
500 _aOpen Access
520 _aThe main objective of the study was to validate the use of canopy temperature depression (CTD) as a rapid early generation screening tool for heat tolerance in wheat. CTD was measured at hot sites in Mexico on F2 derived bulks (BULKS) and on recombinant inbred lines (RILs) derived from the same BULKS, using crosses of parents with different levels of heat tolerance. Results showed (i) CTD measured on BULKS in Mexico were significantly correlated with their average performance at 11 international sites, (ii) CTD was an excellent indicator of which BULKS produced heat tolerant inbred lines evaluated in Mexico, and (iii) CTD measured on RILs were highly significantly correlated with performance in Mexico. These results indicate the robustness of CTD as a selection trait, with potential application at early and intermediate stages of selection. In addition the genetic link between CTD and heat tolerance was demonstrated by showing their association in recombinant inbred lines. Measurements of photosynthesis and leaf conductance on F5 individual plants showed high heritabilities with measurements made on F5 derived F7 sister lines, as well as significant correlations with yield. Results suggest the potential of screening for quantitative traits on individual plants in early generation derived bulks. Genotype by environment interaction in hot wheat growing regions worldwide was tested by growing a set of 60 advanced lines (ALs) selected for heat tolerance in Mexico, at 15 international sites. The results indicate Tlaltizapan to be the best site in Mexico for predicting yields in Bangladesh, NW India, Sudan and Nigeria, and indicated NW India as a good site for heat tolerance screening. Correlation analysis corroborated these observations and indicated late sowing in Obregon as an additional site for heat tolerance screening. Average yield of the 60 ALs at 15 international sites was predicted equally well by CTD or yield, when both were measured in Mexico. Since a reliable yield estimate requires a plot approximately five times bigger than that needed for an estimate of CTD, the use of CTD instead of yield estimates may be considerably more efficient. Alternatively both yield and CTD could be combined in a selection index as a more powerful indicator of heat tolerance. Based on results from the current project, CIMMYT Wheat Breeding Programs are currently evaluating the use of CTD as a selection criterion in preliminary yield trials for heat tolerance. Physiological and morphological data measured in the different experiments suggest that yields under heat stress are source (assimilate) limited. Wheat lines of diverse origin from the Indian and world wheat collections were screened for heat tolerance traits. Preliminary data indicated high levels of expression for CTD, chlorophyll content, rate of biomass accumulation, and kernel weight. A laboratory based screening protocol for membrane thermostability demonstrated a high degree of genetic diversity for the trait in materials from the Indian Bank.
536 _aGlobal Wheat Program
546 _aText in English
591 _aCIMPUBS=107 NO-SCANED 09 (Digitalizar)|Google-Oct-08 Sent printed format|9709|AGRIS 9702|R97-98CIMPU|plant protection|anterior|STAT97|FINAL9798|DSpace 1
594 _aINT1511
595 _aCPC
599 _a64337.JPG
650 1 0 _91800
_aCanopy
_gAGROVOC
650 1 0 _aPlant physiology
_91210
650 1 0 _aResearch policies
_91236
650 1 0 _aResearch projects
_91237
650 1 0 _aSpring crops
_91275
650 1 7 _aWheat
_gAGROVOC
_91310
700 1 _aReynolds, M.P.
_gGlobal Wheat Program
_8INT1511
_9831
700 _97278
_aNagarajan, S.
_eeditor
700 1 _aRazzaque, M.A.
_97279
700 _97280
_aAgeeb, O.A.A.
_eeditor
856 4 _uhttp://hdl.handle.net/10883/1219
_yOpen Access through DSpace
942 _cRE
_2ddc
999 _c53201
_d53201