12.07.2015 Views

the Symposium on Wheats for More Tropical Environments - cimmyt

the Symposium on Wheats for More Tropical Environments - cimmyt

the Symposium on Wheats for More Tropical Environments - cimmyt

SHOW MORE
SHOW LESS
  • No tags were found...

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

50The use of horm<strong>on</strong>als cannot always berecommended, due to <str<strong>on</strong>g>the</str<strong>on</strong>g> largenumbers of horticultural crops in <str<strong>on</strong>g>the</str<strong>on</strong>g>wheat-producti<strong>on</strong> areas. <strong>More</strong>investigati<strong>on</strong> is needed to avoidspraying when and where a drift of finespray or vapors may come in c<strong>on</strong>tactwith nearby sensitive crops orornamental plants.There is an urgent need to plan <strong>for</strong> amajor, c<strong>on</strong>tinuing weed c<strong>on</strong>trolprogram, instead of <str<strong>on</strong>g>the</str<strong>on</strong>g> isolated fieldtrials which have been c<strong>on</strong>ducted sofar.Disease c<strong>on</strong>trolIn central Alajuela, <str<strong>on</strong>g>the</str<strong>on</strong>g> diseases withmost frequent incidence are z<strong>on</strong>ateeyespot (Helminthosporiumgiganteum), H. trttici repentts andcrown rot (Fusarium spp.). In trialscarried out with CIMMYT materialsduring 1978, <str<strong>on</strong>g>the</str<strong>on</strong>g> triticales proved moretolerant to leaf blotch caused byHelminthosporium spp. under naturalinfecti<strong>on</strong> than did <str<strong>on</strong>g>the</str<strong>on</strong>g> wheats.In both central and nor<str<strong>on</strong>g>the</str<strong>on</strong>g>rn Alajuda,when grain maturity and high humiditycoincide, head scab (Fusarium spp.)and saprophytic fungi make <str<strong>on</strong>g>the</str<strong>on</strong>g>irappearance and negatively affect yield.In <str<strong>on</strong>g>the</str<strong>on</strong>g> Cartago area (Sanatorio Duran), ahigh natural incidence of leaf rustappeared in a commercial planting ofSiete Cerros. This permitted <str<strong>on</strong>g>the</str<strong>on</strong>g>determinati<strong>on</strong> of <str<strong>on</strong>g>the</str<strong>on</strong>g> reacti<strong>on</strong> of severalcultivars of wheat and <strong>on</strong>e triticalewhich had been introduced fromCIMMYT. The introduced cultivars wereCananea (Tel), Bobwhite, Anza,Nacozari 76, Pav<strong>on</strong> 76 and Veery 1.With <str<strong>on</strong>g>the</str<strong>on</strong>g> excepti<strong>on</strong> of Nacozari 76, <str<strong>on</strong>g>the</str<strong>on</strong>g>cultivars showed tolerance, withinfecti<strong>on</strong>s of not more than 5% ofPucctnia rec<strong>on</strong>dtta. The virus diseaseknown as alfalfa yellow dwarf has alsoappeared, but is found in low incidence.It is absolutely necesary to c<strong>on</strong>tinueworking, with <str<strong>on</strong>g>the</str<strong>on</strong>g> valuable cooperati<strong>on</strong>of CIMMYT, <strong>for</strong> new sources ofgermplasm with resistance to <str<strong>on</strong>g>the</str<strong>on</strong>g>se ando<str<strong>on</strong>g>the</str<strong>on</strong>g>r diseases.Table 3. Climatological d~anatorio Duran Experiment Stati<strong>on</strong>, TierraBlanca, Cartago, Costa Ri aAverage Average Hoursmaximum minimum Relative ofM<strong>on</strong>th temperature temperature Rainfall humidity sunshine(oC) (oC) (mm) (°/0)January 19.4 8.4 58.1 87.2 3.9February 19.8 8.4 18.3 82.8 4.5March 19.7 8.5 13.9 81.6 4.5April 19.6 8.9 62.1 83.8 4.2May 19.7 8.7 228.0 85.8 3.0June 19.3 8.5 323.8 86.3 2.3July 19.1 8.8 193.3 87.0 2.2August 19.3 9.0 187.8 87.6 2.8September 19.4 8.8 338.2 88.0 2.9October 19.3 8.6 419.8 89.4 2.6November 19.3 8.6 213.7 91.6 2.4December 19.1 8.3 102.8 88.6 2.9!/ Latitude 9 0 56'N, elevati<strong>on</strong> 2,337 mNormal wheat planting time, October, normal wheat harvesting time, MarchAverage yield of five best advanced lines, 7,593 kg/ha

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!