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Questions and Answers in 7 lh Asian Regional Maize Worl\shopPCARRD, LOS BANOS, LAGUNA, PHILIPPINESFebruary 23 - 27, 1998Q: I heard that last year CARGILL was releasing hybrids for acid soils? Do you confirm that? Ifyes, what are they?(Dr. Firdaus Kasim)A: Yes, we are releasing at least 4 hybrids with acid soil tolerance. They are: CPX3007, C- 900M.C-717, and C-5J09.(Dr. Manuel Logrono)Please give clarification on the vector of diseases you mentioned. A species of leafhopper forwhat disease?(Dr. Belen M. Rejesus)A: Dalbulus maydis is the principal vector of the three pathogens of the corn stunt complex. Thepathogens are the corn stunt spiroplasma, Spiroplasma kunkelii; maize bushy stuntphytoplasma; and Maize Rayado Fino virus. The disease complex is not present outside ofNorth, Central, and South America.(Dr. Dnniel Jeffers)Most of your disease evaluation is done at one or two locations only. How do you take care ofraces, if any?(Dr. .N. Singh)A: We breed for mainly polygenic resistance traits which would be expected to be more stable overextended periods of time. We feel that most countries are not capable of following changes inraces which are only described adequately for a few maize diseases. We would like plantings inmore locations to be included in our evaluations to better characterize the genotypes.(Dr. Daniel Jeffers)Q: In this hybrid era, testing for various diseases of economic importance including the stalk rotcomplex, a screening system, especially for CML / other established / new inbred lines, shouldbe initiated to confirm the resistance on selected multi location areas. The data thus obtainedshould be reported using the pattern of Dr. Brewbaker's earlier papers published in the ninetiesusing old inbred lines. For this, environments representing the 5 mega-environments classifiedby CIMMYT could be identified and used for initial testing. May be a regular trial, sent on aninternational basis, could be distributed to plant at selected locations.(Dr. Sangam Lal)A: Yes, a trial system needs to be set up for the characterization of promising lines available in thepublic sector, including CIMMYT, with published results for these activities. This would allowfor a more extensive characterization of the lines for strengths and weaknesses in relation tobiotic and abiotic stresses.(Dr. Daniel Jeffers)Q: How adaptable are the PCR virus-identification methods to small labs now?I commend you for the growing concern about virus diseases. We, who work with sweet comgrown year - round, find viruses to be our primary problem among pathogens.(Dr. James. L. Brewbaker)A: Not much that I know.(Dr. Carlos de Leon)