Spelling suggestions: "subject:"born -- disease anda peut resistance."" "subject:"born -- disease anda pet resistance.""
1 |
Measurement of maize weevil and fungi damage to stored cornMora, Miguel A January 2011 (has links)
Digitized by Kansas Correctional Industries
|
2 |
THE EFFECT OF ACCESSORY CHROMOSOMES ON THE RESISTANCE OF MAIZE TO VIRAL INFECTIONMcGirr, Scott Craig, 1950- January 1977 (has links)
No description available.
|
3 |
Non-cultivated grass hosts of biotypes of corn leaf aphid, Rhopalosiphum maidis (Fitch), Aphididae, HomopteraEsau, Kenneth Lloyd. January 1963 (has links)
Call number: LD2668 .T4 1963 E74 / Master of Science
|
4 |
AFLP and PCR markers for the Ht1, Ht2, Ht3 and Htn1 resistance genes in maizeVan Staden, Derick 12 1900 (has links)
Thesis (PhDAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Maize is undoubtedly South Africa's most important field crop. The identification of
markers and genes for traits of interest is important to sustain the improvement of
maize cultivation. Northern corn leaf blight (NClB) is a disease that occurs worldwide
and can dramatically reduce yield. A number of single dominant resistance
genes have been identified for NClB and some have been mapped. Currently there
are no simple PCR markers for any of these resistance genes, making markerassisted
selection (MAS) difficult.
The aim of this study was to develop PCR markers for the NClB resistance genes
Ht1, Ht2, Ht3 and Htn1 in maize. To accomplish this, the AFlP (amplified fragment
length polymorphism) technique was first optimised. The results indicated that the
Mlul/Msel restriction enzyme combination produces a higher percentage of
polymorph isms when compared to the PstllMsel enzyme combination. It was also
shown that the enzyme combination plays an important role in the percentage of
polymorphic fragments observed, whereas the number of restriction enzymes used in
AFlP analysis only significantly affects the total number of fragments scored.
Populations segregating for the different resistance genes were not available for this
study. Nearly-isogenic lines (Nils) were used in combination with AFlP technology
to identify markers that map close to the genes. AFlP markers common in at least
two resistant or susceptible lines were cloned and converted to PCR markers. Two
commercially available recombinant inbred line (Ril) populations were then used to
map the identified markers.
For Htn1 fifteen polymorphic fragments were present in both resistant lines. They
were selected for sequence specific marker conversion. Seven of the fifteen
sequence characterized amplified region (SCAR) markers were polymorphic on the
Nil pairs and five mapped to one region of maize chromosome 8.05/06. Twenty-one
AFlP markers were identified for Ht1 and four SCAR markers were polymorphic In
the Ht1 Nils. Three of these were mapped to chromosome 2.07. Three AFlP
markers were identified for Ht2 of which two were converted to SCAR markers. Both
SCAR markers were polymorphic on the Ht2 Nils and mapped to chromosome 8.05/06. On the Ht3 NILs, four AFLP markers were identified and two converted
SCAR markers and one microsatellite marker (bnlg1666) were polymorphic. One of
the SCAR markers and the microsatellite marker were mapped to chromosome 7.04
using a RIL population. This reports the first tentative mapping position for the Ht3
locus.
The next step was to determine if a set of marker alleles could be used in a number
of Htn 1 resistance lines to identify a common donor region selected by the breeders.
Nine markers consisting of five SCAR markers, three converted RFLP markers and
one microsatellite marker were used on 16 Htn1 resistant lines. The marker allele of
us3 was in 12 of the 16 lines in coupling with Htn1 resistance. Second was the
marker us5 in 11 of the 16 lines. Using this data 14 of the 16 lines shared a common
introgressed region between the markers us3 and us5. A further common
introgressed region between 11 of the inbred lines was found between the markers
us14 and asg17.
The last aim of this study was to propose a new marker technique that might be more
successful than the AFLP technique in the identification of markers closely linked to
genes. A new marker approach was identified where a MITE (Hbr) primer was used
as an anchor primer in combination with resistance gene analog primers. This was
found to be a highly polymorphic marker technique that could be used to identify
markers and possibly candidate genes. It is a robust technique, which is affordable
since amplifications occur from undigested genomic DNA and the primers mainly
amplify fragments from genic regions. / AFRIKAANSE OPSOMMING: Mielies (Zea mays) is ongetwyfeld Suid Afrika se belangrikste lanbou gewas. Vir
volgehoue opbrengs verbetering is die identifisering van merkers en gene vir
belangrike eienskappe noodsaaklik. Noordelike blaarskroei (NBS) kan opbrengs
wesenlik kan beïnvloed. Tans is daar reeds "n aantal enkel weerstandsgene
geïdentifiseer, maar geen PKR-merkers is beskikbaar vir merker gebaseerde
seleksie nie.
Die doelwit van hierdie studie was om PKR-merkers te ontwikkel vir vier enkel
weerstands gene (Ht1, Ht2, Ht3 en Htn1) teen NBS in mielies. Om die doelstelling te
bereik is die AFLP-tegniek eers geoptimiseer. Op grond van waargenome aantal
polimorfismes, was Mlul/Mse/"n beter restriksie ensiem kombinasie as Pstl/Msel. In
die studie is ook bewys dat die aantal (meer as twee) restriksie ensieme wat gebruik
word slegs die aantal fragmente, en nie die persentasie polimorfismes, wesenlik
beïnvloed nie.
Geen segregerende populasie was vir die verskillende gene beskikbaar nie. Naby
isogeniese lyne (NILe) is daarom in kombinasie met die AFLP-tegniek gebruik om
merkers te identifiseer wat naby die gene karteer. Alleenlik polimorfiese merkers wat
in ten minste twee weerstand biedende of vatbare lyne voorgekom het, is gekloneer
en omgeskakel na PKR-merkers. Daarna is twee kommersiële rekombinante
ingeteelde lyn populasies gebruik om die gene te karteer.
Vyftien fragmente is gevind wat gekoppel was met die Htn1 weerstand. Sewe van
hierdie merkers is omgeskakel in polimorfiese SCAR-merkers waarvan vyf gekarteer
is in een gebied op chromosoom 8.05/06. Een-en-twintig AFLP-merkers is
geïndentifiseer vir Ht1 en vier is omgeskakel na polimorfiese SCAR-merkers. Drie
hiervan is gekarteer op chromosoom 2.07. Drie AFLP-merkers is geïndetifiseer vir
Ht2 waarvan 2 omgeskakel is na polimorfiese SCAR-merkers. Altwee hierdie
merkers is gekarteer op chromosoom 8.05/06. Op die Ht3 lyne is vier AFLP-merkers
geïdentifiseer waarvan twee omgeskakel is na polimorfiese SCAR-merkers. Een
mikrosatelliet merker (bnlg1666) is ook gevind wat die selfde polimorfiese patroon
wys op die Ht3 lyne. Die mikrosateliet en een van die SCAR-merkers het gekarteer op chromosomale posisie 7.04. Hierdie is die eerste tentatiewe posisie vir die Ht3
lokus.
Die volgende stap was om te bepaal of "n stel polimorfiese merker-allele gebruik kan
word om die donor DNA-segment te identifiseer wat die plantteiers geselekteer het.
Nege PKR-merkers wat bestaan het uit vyf SCAR-merkers, 3 omgeskakelde RFLP
merkers en een mikrosateliet is gebruik op 16 Hnt1 weerstandslyne. Us3 was die
merker alleel wat in die meeste gevalle gekoppel was met die Htn1 weerstandslyne
(12/16). Tweede was die merker us5 (in 11 van die 16 lyne). Uit die data blyk dit dat
14 van die 16 lyne "n donor segment het wat beide merkers us3 en us5 bevat.
Merkers us14 en asg17 het in 11 van die 16 bestande lyne saam voorgekom.
Die laaste doelstelling van hierdie studie was om "n nuwe tegniek te ontwikkel wat
dalk meer suksesvol as AFLPs kan wees om merkers te identifiseer nabyaan gene.
"n Nuwe tegniek word voorgestel waar "n MITE (Hbr) inleier gebruik kan word in
kombinasie met weerstandgeen-analoog inleiers. Dit is gevind dat hierdie
kombinasie van inleiers "n hoogs polimorfiese band patroon gee en dat die merkers
ook dalk kandidaat-gene kan wees. Die tegniek is maklik uitvoerbaar, relatief
goedkoop en maak gebruik van onverteerde genomiese DNA. Die fragmente wat
geamplifiseer word is hoofsaaklik vanaf geenryke areas.
|
5 |
Studies of resistance of 92 sorghum and 38 maize cultivars to 4 species of stored-product insectsManeechoti, Payuha January 2011 (has links)
Digitized by Kansas Correctional Industries
|
6 |
Growth and development of the southwestern corn borer on corn (Lepidoptera: Pyralidae)Whitworth, Robert J January 2011 (has links)
Typescript. / Digitized by Kansas Correctional Industries
|
7 |
Agronomic evaluation of short season quality protein maizeSpaner, Dean Michael January 1992 (has links)
The introduction of Quality Protein Maize (QPM), hard endosperm opaque-2 maize, into northern temperate maize growing areas is a desirable breeding objective. In topcrosses with opaque-2 testers, in diallel combination, as inbreds per se, and in inbred disease screening nurseries, some QPM lines performed better than or equal to the best local checks. In general, while agronomic potential is high for some lines and gains from selection are statistically possible, longer days to flowering intervals and higher levels of moisture at harvest than check hybrids indicated a need to improve adaptation for the locations studied. Methodology experiments indicated that detasselling of check hybrids is a suitable experimental method to facilitate the inclusion of normal endosperm local checks into QPM performance tests. The screening for Fusarium graminearum resistance in the seedling stage has not been proven to be a viable alternative to field scale ear inoculation screening procedures. (Abstract shortened by UMI.)
|
8 |
Resistance of maize silk to Fusarium graminearumReid, Lana M. (Lana Marie) January 1991 (has links)
The characteristics and inheritance of maize silk resistance to Fusarium graminearum ear rot were investigated. In an in vitro test, genotypic differences in the degradation of detached silk tissue by F. graminearum were correlated to field evaluations of resistance. Susceptibility to infection decreased with silk age. Total phenolics of silk channel silk tissue increased in response to infection in resistant inbreds but decreased in susceptible inbreds. The flavones iso-orientin, iso-vitexin, maysin, luteolin, and apigenin were identified in the silk. No significant genotype by isolate interaction effects were found when 13 inbred lines were inoculated with three F. graminearum isolates. Simple models of quantitative and qualitative inheritance were not adequate to explain the inheritance of resistance. Disease severity ratings were bimodally distributed in the F$ sb1$, F$ sb2$, and backcross generations. In a complete diallel cross among 12 inbred lines, general and specific combining ability effects were significant for both disease incidence and disease severity. A screening of 12 accessions of exotic maize germplasm with resistance to either Aspergillus flavus or Heliothis zeae, identified several possible new sources of resistance to F. graminearum. Visual evaluations of resistance were correlated to deoxynivalenol levels of the ear.
|
9 |
Variation for resistance to Fusarium graminearum ear rot in selfed families from the corn population Zapalote ChicoKrsikapa, Nenad. January 1997 (has links)
Experiments were conducted to assess the variation for resistance to Fusarium graminearum ear rot among selfed lines from the Zapalote Chico corn population. It was already known that Zapalote Chico possesses some resistance to corn earworm (Heliothis zeae) and variation in Fusarium graminearum ear rot symptom severity had been observed within the population. During two years of experiments, 47 S4- and S5-generation lines were inoculated and ear rot severity was assessed. In addition, eight pigmentation traits and eight morphological traits were recorded. Lines showed significant differences for all recorded traits. Associations were not strong among morphological traits, but were fairly strong among pigmentation traits. Ear rot symptom severity did not seem to be associated with any other trait. The source population and inbred lines exhibited broad ranges of variation and similar bimodal distributions of ear rot symptom severity ratings. Despite significant differences among lines within experiments none of the lines showed distinct and consistent resistance over two years of experiments. It seems that Zapalote Chico lines do not have environmental stability and sufficient potential to be considered worthwhile source of resistance for ear rot.
|
10 |
Quantitative genetic analysis of recombinant inbred lines (RIL) from tropical maize singlecrossesMoon, Hyeon Gui January 1995 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 228-240). / Microfiche. / xx, 240 leaves, bound ill. (some col.) 29 cm
|
Page generated in 0.1533 seconds