Role of Haploidy in Improvement of Vegetables

Presented by:

Shahid Mehmood (2003-ag-1594)fragrance36@yahoo.com+92 300 6990799

M.Sc(Hons.) Horticulture 3rd SemesterUniversity of Agriculture Faisalabad

What is Improvement ? (Crop improvement)

• Increased quality and yield of the crop • Increased tolerance of environmental

pressures (salinity, extreme temperature, drought etc.) • Resistance to viruses, fungi and

bacteria,nematodes etc.• Increased tolerance to insect pests • Increased tolerance of herbicides

What is Improvement ?

Between the lines…….why was done?

• Each time Need based

(population increase, natural disasters etc.)

• Any target when achieved was called

an “improvement”

e.g. any resistance, tolerance, yield increase etc.…..

Methods of crop improvement

• Classical Breeding

• Modern Breeding

Mutation Breeding

Haploid Production (Haploidy)

Ploidy ManipulationGenetic Engineering

Haploid Production (Haploidy)

Haploid - gametic number of chromosomes

A. Reduce time for variety development, e.g. 10 to 6 years or less

B. Homozygous recombinant line can be developed in one generation instead of after numerous backcross generations

C. Selection for recessive traits in recombinant lines is more efficient since these are not masked by the effects of dominant alleles

Agricultural applications for haploids - Rapid generation of homozygous genotypes after chromosome doubling

Haploid Production (Haploidy)

• Natural occurrence rare, confined to a few species

• Major contributions of plant tissue culture research to crop improvement

• Detection of mutations, usually recessive, difficult to detect

• Isolation of resistant cell lines via in vitro selection• Exclusively male plants by doubling chromosomes (Asparagus )

(Eimert, k. et al. 2003) • Plants from fused protoplasts…regeneration problem

(in somatic hybridization

Double Haploids (DHs)• homozygous (true breeding )• rapid development from microspores to DH

(8 months in Brassica napus)

in vitro technology allows production and manipulation of very large numbers of individuals at very low cost

• 100% homozygosity of doubled haploidElimination of dominance variationMuch less progeny needed Reduction of 3-5 years for cultivar release

• Genetic Study No risk of herterozygosity Quantitative gene inheritance Estimation of additive variances

• Mapping Study Permanent population No risk of herterozygosity

can be repeated anytime can be used in different Lab can be used by different researchers data can be accumulated

Methods to Haploid Production

Androgenesis ..Cultured Anther or isolated microspore

Gyonogenesis Cultured unfertilized ovaries

Wide Hybridizationcross followed by chromosome elimination

Partehnogenesis

embryo by pseudogamy,semigamy apogamy

(Maluszynski et al. 2003b)

Review

Haploids in the Improvement of Cucurbitaceae Species

• Dumas de Vaulx induced the first haploid plants of the Cucurbitaceae by interspecific crossing between C. melo L. and C. ficifolius.

(Dumas de Vaulx 1979) • The stimulation of haploid parthenogenesis through

pollination with irradiated pollen was successfully applied to haploid production in

melon (Lotfi et al. 2003)watermelon (Sari et al. 1994) cucumber (Caglar and Abak

1999)squash (Kurtar et al. 2002 )

Haploids in the Improvement of Cucurbitaceae Species

• The irradiation doses of gamma rays and the maternal geno-types significantly affected the frequency of haploid

embryo induction. ( Sauton 1989)

• obtained haploid plants both from anther culture and unpollinated ovules of Cucurbita pepo.

( Metwally et al 1998a,b) • In courgettes and cucumber an effective method was

established for the development of haploid plants through in vitro gynogenesis

(Gémes Juhász et al. 1996, 2002a).

Haploids in the Improvement of Liliaceae Species

• In the genus Allium, only gynogenesis has been used effectively to produce haploid plants, since efforts in the

anther culture of onion failed. (Keller 1990)

• gynogenically derived haploid plants have been success-fully produced in onion and shallot, and some attempts

have been made in leek. (Schum et al. 1993). • In Lilium Species , successful gynogenesis in ovary

culture of lily (Prakash and Giles 1986)

Haploids in the Improvement of Asparagaceae

• Sex expression in asparagus is inherited as though controlled by a single-gene factor dominant for maleness

(Ellison 1986)

• Compared to female plants, male plants have better earliness, have better yield (more spears per plant) and longer life, which are important and long-known

characteristics. (Ellison et al. 1960)

• Male plants were produced by Anther Culture

(Doré 1974)

Haploids in the Improvement of Chenopodiaceae

• In sugar beet , In vitro androgenesis has been

attempted numerous times but with very limited success (van Geyt et al. 1987)

• Gynogenesis has proven to be the most successful method for haploid production and the only approach to produce haploids of male sterile lines

(Gürel et al. 2000)• highest number of haploid plants could be obtained when

using male-fertile donors. (Ferrant and Bouharmont 1994)

Haploids in the Improvement of Araceae

• In Spathiphyllum wallisii gynogenic plants have been

produced from the excised ovules . . Eeckhaut et al. (2001)

Haploids in the Improvement of Umbelliferae

• Two haploid plants of carrot were obtained by irradiated pollen-induced parthenogenesis (Rode et al. 1987)

• Successful protocol of carrot (Dacus carota L.)

androgenesis.(Andersen et al. 1990)

Haploids in the Improvement of Crucifers

• Haploid induction in cabbage (B. oleracea var. capitata) was less efficient in comparison to other morphological

forms such as broccoli Brussels’ sprouts and cauliflower (Rudolf et al. 1999)

• The possible improvement of non-responsive genotypes with regard to embryogenic efficiency by crossing with a responsive genotype. This can be very useful, as the absence of genotype-independent protocols for haploid production limits the use of the DH procedure in cabbage breeding. (Rudolf et al. 1999)

Haploids in the Improvement of Crucifers

• Microspore or anther culture is now routinely used for the production of homozygous lines in broccoli breeding, and regenerated plant populations from anther culture

represent a mixture of ploidy. (Wang et al. 1999)

Some Agronomical Characteristics of Doubled Haploid Lines Produced by Irradiated Pollen Technique an

Parental Diploid Genotypes in Melons

Table 1. Some plant growth characteristics and yields of double haploid (DH) lines and starting materials (SM).Starting Double Early Yield Total Plant Node Number Main StemMaterials Haploid kg m-2 Yield Height (nodes plant-1) Diameter

Lines kg m-2 (cm) (mm)T1

0.1 p 6.7 b-h 206 a-e 29 abc 10.2 a-fA4 3.0 g-p 6.4 b-h 211 a-d 34 a 11.7 abc

5/114.6 c-l 6.6 b-h 195 a-g 27 b-h 10.6 a-e

B5 4.8 c-k 6.5 b-h 162 d-j 24 b-k 11.3 a-dB7 0.3 op 3.4 h 120 j 21 ijk 10.6 a-eB9 2.7 h-p 6.8 b-h 152 e-j 23 e-k 10.1 a-f

8/124.5 c-m 8.5 a-f 174 d-j 27 b-h 10.6 a-e

C1 3.5 f-p 5.6 d-h 139 g-j 25 b-j 10.6 a-eC3 2.2 i-p 7.0 b-g 171 d-j 27 b-g 10.1 a-fC5 3.0 g-p 5.4 d-h 135 hij 22 g-k 9.8 a-fC7 4.2 d-n 7.3 b-g 160 d-j 23 f-k 9.0 defC8 3.6 f-o 6.1 c-h 161 d-j 23 d-k 9.1 c-fC9 1.1 m-p 8.3 a-f 159 d-j 23 e-k 10.7 a-eC10 2.1 j-p 5.1 e-h 138 hij 22 g-k 7.8 fC13 9.0 a 11.3 a 207 a-e 24 b-k 9.0 c-fC17 2.5 h-p 6.0 c-h 150 e-j 24 b-k 10.3 a-C18 4.2 d-n 7.4 b-g 160 d-j 26 b-j 10.9 a-eC19 0.8 nop 5.9 c-h 138 hij 22 h-k 9.0 def

Continue…..

9/257.0 a-f 8.4 a-f 212 a-d 27 b-h 11.4 a-d

D5 7.1 a-e 8.2 a-f 177 c-i 28 b-g 11.5 a-dD10 6.5 a-f 7.8 a-g 174 d-j 26 b-j 11.0 a-eD11 7.2 a-e 8.8 a-d 185 b-h 28 b-g 10.6 a-eD13 8.6 ab 9.2 abc 166 d-j 26 b-j 9.9 a-fD20 4.3 c-m 5.9 c-h 159 d-j 24 c-k 11.6 a-dD25 5.2 b-j 6.7 b-h 167 d-j 27 b-i 9.8 a-fD34 1.3 l-p 5.6 d-h 157 d-j 19 k 10.0 a-f

13/13 4.0 d-n 6.3 c-h 212 a-d 29 a-d 10.1 a-fE8 0.1 p 8.2 a-f 232 abc 26 b-j 10.7 a-eE13 5.3 b-j 6.6 b-h 241 ab 25 b-j 11.2 a-dE14 7.3 a-d 8.6 a-e 245 a 25 b-j 12.4 abE19 2.1 j-p 5.6 d-h 200 a-f 26 b-j 10.6 a-eE21 7.7 abc 9.9 ab 203 a-f 25 b-j 11.0 a-eE25 0.5 op 6.4 b-h 190 a-h 27 b-h 11.2 a-d

14/1 1.7 k-p 6.2 c-h 178 c-i 24 c-k 10.5 a-eG2 5.8 a-h 8.0 a-f 174 d-j 27 b-g 11.0 a-eG7 6.4 a-g 6.5 b-h 182 c-h 29 ab 11.7 abcG8 4.2 d-n 5.4 d-h 147 f-j 26 b-j 10.5 a-eG20 5.6 a-i 8.1 a-f 188 b-h 28 b-g 12.4 aG22 5.0 c-k 8.4 a-f 187 b-h 28 a-e 11.4 a-dG25 5.3 b-j 6.0 c-h 177 d-j 26 b-j 10.6 a-eG28 3.8 e-o 4.4 gh 146 f-j 25 b-j 10.0 a-fG34 4.2 d-n 5.3 e-h 147 f-j 26 b-j 10.2 a-fG35 4.3 c-m 6.8 b-h 162 d-j 25 b-k 11.2 a-d

Contiue…

14/2 5.5 b-j 7.2 b-g 178 c-i 27 b-h 9.9 a-fH1 5.0 c-k 7.9 b-g 147 f-j 25 b-k 11.5 a-dH2 5.1 c-k 7.3 b-g 161 d-j 27 b-h 10.1 a-fH5 3.0 g-p 4.9 fgh 124 ij 25 b-k 9.7 b-fH14 5.2 b-j 7.0 b-g 173 d-j 26 b-i 11.0 a-eH27 5.3 b-j 6.7 b-h 190 a-h 25 b-j 9.6 c-f

58/2 6.4 a-g 8.3 a-f 158 d-j 27 b-h 11.2 a-d48/131 1.2 l-p 6.8 b-h 160 d-j 21 jk 9.4 c-f

I5 5.1 c-j 9.2 abc 168 d-j 24 d-k 9.6 c-fI7 1.1 m-p 7.6 b-g 188 a-h 28 b-f 10.7 a-e

61/13 0.4 op 8.1 a-f 232 abc 28 a-e 10.0 a-fK2 5.1 c-k 6.1 c-h 170 d-j 28 a-f 9.7 a-fK4 1.3 l-p 7.3 b-g 233 abc 26 b-j 8.4 ef

Means of SM 3.5 7.3 190 27 10.4Means of DH 4.2 6.9 172 25 10.5MSD (1%) 3.5 3.6 57 6 2.7

• * First column shows starting materials (diploid lines). • ** Second column shows dihaploid lines produced by irradiated pollen techniques. • *** Same letter indicates the absence of significant difference at p = 0.01 Tukey tests.

Table 2. Fruit characteristics of double haploid (DH) lines and starting materials (SM).Starting Double Fruit Weight Fruit Fruit Length Seed Cavity Seed Cavity Rind Flesh TSS (%)Materials* Haploid (g) Diameter (cm) Diameter Length (cm) Thickness Thickness

Lines** (cm) (cm) (mm) (mm)

T1 1196 d-o*** 12.4 a-j 14.8 g-n 6.1 a-g 9.1 h-p 4.2 a-d 17.9 a-i 8.0 a-lA4 1218d-o 11.8 b-n 14.4 h-p 5.9 b-g 9.4 h-o 5.2 a-d 13.6 e-l 6.3 h-l

5/11 767 o-u 10.9 h-p 12.5 k-t 4.8 g 7.2 n-q 4.3 a-d 15.7 b-l 9.5 a-gB5 743 o-u 10.5 k-q 12.7 j-t 4.7 g 8.0 j-q 6.4 a-d 17.1 a-k 9.2 a-hB7 468 tu 9.3 pq 9.7 t 4.9 g 5.9 q 3.1 d 11.7 jkl 8.5 a-kB9 824 m-u 10.8 i-q 13.1 i-t 5.0 g 7.8 l-q 6.1 a-d 16.4 a-l 9.3 a-h

8/12 1135 f-o 12.6 a-h 14.1 h-r 6.0 b-g 9.2 h-p 6.4 a-d 18.4 a-h 8.7 a-jC1 798 n-u 11.0 h-p 15.0 f-n 5.4 b-g 8.7 i-q 4.1 bcd 13.8 d-l 9.0 a-iC3 896 k-u 11.0 h-p 10.9 p-t 5.7 b-g 7.2 n-q 5.2 a-d 15.0 d-l 8.2 a-lC5 558 stu 10.3 m-q 10.5 rst 5.1 fg 6.4 pq 3.8 d 12.7 g-l 8.3 a-kC7 909 k-u 12.2 b-k 13.0 j-t 5.8 b-g 8.2 i-q 5.3 a-d 18.1 a-i 7.4 c-lC8 1001 i-s 11.8 b-m 12.6 k-t 5.3 b-g 7.8 l-q 5.2 a-d 18.1 a-i 6.6 f-lC9 1210 d-o 12.6 a-h 16.3 e-j 5.8 b-g 11.7 c-h 6.4 a-d 12.1 i-l 8.4 a-kC10 461 u 9.0 q 16.3 e-j 5.2 c-g 6.7 n-q 5.9 a-d 12.4 i-l 10.5 abcC13 1403 c-j 12.6 a-h 14.2 h-q 5.9 b-g 11.1 c-i 4.8 a-d 18.6 a-g 7.2 e-lC17 836 l-u 11.3 h-o 11.4 n-t 6.9 ab 7.8 l-q 4.6 a-d 11.1 kl 6.2 h-lC18 900 k-u 11.3 h-o 13.5 h-s 5.8 b-g 8.7 i-q 4.9 a-d 15.1 d-l 10.4 a-dC19 605 r-u 10.0 n-q 10.6 q-t 6.2 a-g 7.7 m-q 4.7 a-d 11.5 jkl 7.3 d-l

continur…..

9/25 1071 h-r 11.5 e-n 15.4 f-m 6.0 b-g 10.8 d-k 3.5 d 15.9 b-l 5.4 klD5 1556 a-g 13.4 a-d 16.8 d-i 7.1 a 11.9 c-h 5.8 a-d 18.5 a-h 7.0 e-lD10 1203 d-o 12.6 a-h 15.0 f-n 6.9 abc 9.4 h-o 6.4 a-d 15.4 c-l 6.6 f-lD11 939 j-t 11.5 f-n 14.1 h-r 5.6 b-g 9.4 h-o 4.7 a-d 15.3 c-l 5.2 lD13 1369 c-k 13.2 a-f 15.3 f-k 5.8 b-g 10.4 e-m 3.5 d 16.3 b-l 6.0 i-lD20 860 l-u 10.9 h-p 12.6 k-t 5.2 d-g 7.9 k-q 4.4 a-d 15.1 d-l 7.5 c-lD25 1072 h-r 10.8 i-q 13.3 h-t 6.3 a-g 9.3 h-p 4.0 bcd 15.7 b-l 6.1 i-lD34 576 stu 9.6 opq 10.0 st 5.3 b-g 8.1 j-q 5.8 a-d 10.9 l 5.9 jkl

13/13 1074 h-r 12.3 b-k 13.1 i-t 6.2 a-g 8.0 j-q 4.9 a-d 15.7 b-l 7.4 c-lE8 886 l-u 10.3 m-q 14.8 g-n 4.9 g 10.9 d-j 7.7 abc 16.8 a-l 7.7 b-lE13 1458 b-i 11.4 g-n 23.2 a 6.8 a-e 16.1 ab 5.1 a-d 13.5 f-l 6.4 g-lE14 1782 abc 12.2 b-k 23.2 a 6.1 a-g 18.1 a 4.9 a-d 15.8 b-l 6.4 g-lE19 960 j-s 12.5 a-i 11.4 n-t 6.2 a-g 6.6 opq 3.9 cd 15.5 c-l 7.1 c-lE21 1618 a-e 12.3 a-k 20.5 abc 5.1 efg 14.1 bc 3.9 cd 18.9 a-f 6.5 g-lE25 634 q-u 10.4 l-q 10.6 q-t 6.9 ab 7.5 m-q 3.7 d 12.6 h-l 10.8 ab

14/1 1083 g-q 11.7 c-n 14.2 h-q 4.9 g 9.6 g-m 6.1 a-d 19.0 a-f 10.4 a-dG2 1144 e-p 12.4 a-j 15.7 f-l 5.9 b-g 10.7 e-l 6.3 a-d 18.5 a-h 10.9 aG7 1147 e-p 11.0 h-p 17.0 c-h 5.5 b-g 12.5 c-g 5.2 a-d 15.9 b-l 8.6 a-jG8 1637 a-d 10.9 h-p 12.0 l-t 5.2 c-g 7.7 m-q 3.5 d 16.2 b-l 8.9 a-jG20 1288 d-m 13.4 a-d 14.1 h-r 6.8 abc 9.3 h-p 6.7 a-d 18.5 a-h 8.6 a-jG22 1268 d-n 12.2 b-k 16.1 e-k 5.8 b-g 10.3 f-m 6.1 a-d 17.9 a-i 8.2 a-lG25 1471 b-i 12.2 b-l 20.1 a-d 5.5 b-g 13.8 bcd 4.6 a-d 18.7 a-f 7.6 c-lG28 1305 c-l 13.2 a-g 14.6 h-o 6.1 a-g 9.2 h-p 4.6 a-d 19.8 a-d 9.1 a-iG34 636 q-u 10.7 i-q 10.9 o-t 5.9 b-g 7.0 n-q 6.6 a-d 14.4 d-l 7.1 e-lG35 801 n-u 11.3 h-o 11.7 n-t 5.5 b-g 6.9 n-q 5.6 a-d 16.5 a-l 9.9 a-e

Continue….

14/2 892 k-u 11.6 d-n 11.9 m-t 6.1 b-g 8.3 i-q 5.8 a-d 15.9 b-l 9.5 a-gH1 770 o-u 11.7 c-n 13.5 h-s 5.8 b-g 8.0 j-q 5.4 a-d 16.6 a-l 9.5 a-gH2 836 l-u 11.8 c-n 12.0 m-t 5.6 b-g 7.6 m-q 5.5 a-d 15.2 c-l 9.2 a-hH5 585 stu 10.3 m-q 10.5 rst 5.3 b-g 6.7 n-q 4.3 a-d 13.1 f-l 9.1 a-iH14 713 p-u 11.2 h-o 10.4 rst 5.9 b-g 7.5 m-q 7.0 a-d 16.4 a-l 10.1 a-eH27 651 q-u 10.6 j-q 10.8 p-t 5.6 b-g 6.9 n-q 6.3 a-d 14.7 d-l 8.9 a-i

58/2 879 l-u 11.8 b-n 12.4 k-t 5.5 b-g 7.9 k-q 5.7 a-d 17.4 a-j 8.8 a-j48/131 1983 a 13.3 a-e 20.7 ab 5.8 b-g 13.3 bcde8.2 a 21.2 abc 8.1 a-l

5 1563 a-f 14.1 a 18.6 b-f 6.6 a-f 11.8 c-h 5.7 a-d 22.4 a 7.1 e-lI7 795 n-u 10.3 m-q 13.5 h-s 4.7 g 8.3 i-q 5.1 a-d 16.9 a-k 9.7 a-f

61/13 1536 a-h 13.5 ab 14.9 g-n 6.8 a-d 10.7 e-l 5.8 a-d 19.5 a-e 8.1 a-lK2 1403 c-j 11.8 b-m 19.6 a-e 5.7 b-g 13.2 b-f 5.3 a-d 17.5 a-j 8.5 a-jK4 1899 ab 13.4 abc 18.3 b-g 5.2 d-g 12.0 c-h 8.0 ab 21.6 ab 7.4 d-l

Means of SM 1162 12.2 14.4 5.8 9.4 5.5 17.7 8.4Means of DH 1036 11.5 14.1 5.8 9.4 5.2 15.8 7.9MSD (1%) 478 1.8 3.7 1.6 3.0 4.0 6.0 3.1

* First column shows starting materials (diploid lines). ** Second column shows dihaploid lines produced by irradiated pollen techniques. *** Same letter indicates the absence of significant difference at p = 0.01 Tukey tests.

(Nebahat SARI 2002)

Powdery mildew (Sphaerotheca fuliginea) resistance in

melon is selectable at the haploid level Table 1. Responses of diploid and haploid plants to four races of S. fuliginea and histology of the stages of infection

Genotype Ploidy No. of Responses and shape of conidiaplantstested Race 1 Race 5 Race 6 Race 7

Fuyu 3 Diploid 1 Sa (c)c S (c) S (c) S (c)Haploid 1 S (c) S (±) S (c) S (c)

PMR 45 Diploid 1 Rb (g)d S (c) R (g) S (c)Haploid 2 R (g) S (±)e R (g) S (c)

WMR 29 Diploid 1 R (g) S (c) R (g) R (g)Haploid 2 R (g) S (±) R (g) R (g)

Fuyu 33PMR 45 Diploid 5 R (g) S (±) R (±) S (±)Haploid 7 R (g) S (±) R (g) S (c)

6 S (c) S (±) S (c) S (c)Fuyu 33WMR 29 Diploid 5 R (g) S (±) R (±) R (±)

Haploid 10 R (g) S (±) R (g) R (g)2 S (c) S (±) S (c) S (c)

• a S: susceptible. b R: resistant.

• c c: hyphal development and conidial initiation. d g: germ-tube and haustorium formation. e ±: Not tested

(M. Kuzuya et al 2003)

Fig. 1. (A) Responses to S. fuliginea race 1 of leaf discs from haploid (left) and diploid (right) plants of Fuyu 3 and WMR 29. (B) Responses to S. fuliginea race 1 of leaf discs from diploid plants (middle) of Fuyu

3 (F), and WMR 29 (W), and haploid plants (round) that were generated from the F1 progeny of a Fuyu 33WMR 29 cross.

• Fig. 2. Histological observations of S. fuliginea infection of leaf discs from diploid melon plants. (A) Inoculated conidia from a leaf disc of Fuyu 3. Scale bar=10 mm. (B) Germ-tube development 4 h after inoculation of a leaf disc of Fuyu 3. Scale bar=10 mm. (C) Haustoria formation at 24± 48 h after inoculation of a leaf disc of Fuyu 3. Scale bar=10 mm. (D) Multiple haustoria, 48±120 h after inoculation of a leaf disc of PMR 45. Scale bar=10 mm. (E) Hyphal development and new conidia initiation on a leaf disc of Fuyu 3, 120 h after inoculation. Scale bar=50 mm. g: Germ tube; h: haustorium; hp: hyphae; c: conidia.

Fast and reliable detection of doubled-haploids inAsparagus officinalis by stringent RAPD-PCR

(Eimert, k. et al. 2003)

Fast and reliable detection of doubled-haploids inAsparagus officinalis by stringent RAPD-PCR

Production of an auxinic herbicide-resistant microspore-deriveddoubled haploid wild mustard (Sinapis arvensis L.) plant

(J. Mithila, 2007)

Attempt to select cucumber (Cucumis sativus) double haploid lines to downy mildew tolerance by molecular markers1

(Nebahat SARI, 2008)

• all plants were classified as monohaploids (n=7) • vegetatively propagated to provide material for chromosome

doubling. • 240 primers were evaluated• Five genotypes

two 2n regenerants of ‘Polan’ one 1n ‘Izyd’ one 2n regenerants one 1n of regenerant of ‘Frykas’)

• RAPD analysis was performed differentiating between susceptible and resistant plants among haploid and DH plants developed from hybrids

‘Polan’ (susceptible ‘Frykas’ and ‘Izyd’ (both resistant)

• Nine primers generated polymorphic bands that differentiated haploid and DH

• Five primers (A14, C11, D18, E2, and E14) produced a band present in both, H and DH susceptible plants derived from ‘Polan .

• Three primers (B6, E15 and E20) generated an unique band for H and DH plants

• One primer (D13) generated one band specific for resistant plants and one band specific for susceptible plants

• Bands were 580 bp and 1480 bp in size for the resistant and the susceptible plants, respectively.

Prospect of using Doubled Haploids

• Tool to attain homozygosity much earlier than classical breeding…can be used extensively.

• DHs’ performance has been equal or even lesser….necessitating extensive research is needed after being developed

• No special resistance or tolerance etc.• Crossing DHs with commercial hybrids

may serve the purpose.

• Genetically stable inbreds can be obtained and applied in a productive breeding program.