The elite Indian rice variety, Naveen is highly susceptible to major biotic and abiotic stresses such as blast, bacterial blight (BB), gall midge (GM) and drought which limit its productivity in ...rainfed areas. In the present study, a combined approach of marker-assisted forward (MAFB) and back cross (MABC) breeding was followed to introgress three major genes, viz., Pi9 for blast, Xa21 for bacterial blight (BB), and Gm8 for gall midge (GM) and three major QTLs, viz., qDTY.sub.1.1, qDTY.sub.2.2 and qDTY.sub.4.1 conferring increased yield under drought in the background of Naveen. At each stage of advancement, gene-based/linked markers were used for the foreground selection of biotic and abiotic stress tolerant genes/QTLs. Intensive phenotype-based selections were performed in the field for identification of lines with high level of resistance against blast, BB, GM and drought tolerance without yield penalty under non-stress situation. A set of 8 MAFB lines and 12 MABC lines with 3 to 6 genes/QTLs and possessing resistance/tolerance against biotic stresses and reproductive stage drought stress with better yield performance compared to Naveen were developed. Lines developed through combined MAFB and MABC performed better than lines developed only through MAFB. This study exemplifies the utility of the combined approach of marker-assisted forward and backcrosses breeding for targeted improvement of multiple biotic and abiotic stress resistance in the background of popular mega varieties.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Unfavorable climatic changes have led to an increased threat of several biotic and abiotic stresses over the past few years. Looking at the massive damage caused by these stresses, we ...undertook a study to develop high yielding climate-resilient rice, using genes conferring resistance against blast (
Pi9
), bacterial leaf blight (BLB) (
Xa4, xa5, xa13, Xa21
), brown planthopper (BPH) (
Bph3, Bph17
), gall midge (GM) (
Gm4, Gm8
) and QTLs for drought tolerance (
qDTY
1.1
and
qDTY
3.1
) through marker-assisted forward breeding (MAFB) approach.
Result
Seven introgression lines (ILs) possessing a combination of seven to ten genes/QTLs for different biotic and abiotic stresses have been developed using marker-assisted selection (MAS) breeding method in the background of Swarna with drought QTLs. These ILs were superior to the respective recurrent parent in agronomic performance and also possess preferred grain quality with intermediate to high amylose content (AC) (23–26%). Out of these, three ILs viz., IL1 (
Pi9
+
Xa4
+
xa5
+
Xa21
+
Bph17
+
Gm8
+
qDTY
1.1
+
qDTY
3.1
), IL6 (
Pi9
+
Xa4
+
xa5
+
Xa21
+
Bph3
+
Bph17
+
Gm4
+
Gm8+ qDTY
1.1
+
qDTY
3.1
) and IL7 (
Pi9+ Xa4
+
xa5
+
Bph3
+
Gm4
+
qDTY
1.1
+
qDTY
3.1
) had shown resistance\tolerance for multiple biotic and abiotic stresses both in the field and glasshouse conditions. Overall, the ILs were high yielding under various stresses and importantly they also performed well in non-stress conditions without any yield penalty.
Conclusion
The current study clearly illustrated the success of MAS in combining tolerance to multiple biotic and abiotic stresses while maintaining higher yield potential and preferred grain quality. Developed ILs with seven to ten genes in the current study showed superiority to recurrent parent Swarna+drought for multiple-biotic stresses (blast, BLB, BPH and GM) together with yield advantages of 1.0 t ha
− 1
under drought condition, without adverse effect on grain quality traits under non-stress.
PDF
