Bulked segregant analysis for developing genetic markers of drought tolerance in faba bean (vicia faba l.)‎

Abstract EN

Afield experiment was conducted to study the response of two contrasting drought tolerant parents (L8 and L3), their F1, F2 and two comparative varieties (G716 and G461) to cultivation under natural rain conditions at Mary out region.

Seed yield / plant and its components revealed significant differences among all genotypes for all traits recorded.

The F2 tolerant sergeants group surpassed all other genotypes tested for seed yield/plant.

This is attributed mainly to number of pods / plant and partially to seed index.

The results of protein markers indicated that parental drought tolerant line and F2 tolerant sergeant group had a specific band of 87KDa molecular weight which could be used to distinguish the drought tolerant genotypes among others, for instance F1 cross (L3xL8) and Giza 461 gave the same band.

Acid phosphatase isozyme patterns didn’t give clear cut markers for the discrimination between drought tolerant and drought sensitive genotypes.

A positive band for drought sensitive genotypes as it was observed in F2S and L8 sensitive parent.

Α-esterase (band No.6) and β-esterase (band No.5) isozyme patterns could be used to distinguish the drought sensitive genotypes among others.

Bulked sergeant analysis was used to analyze DNA extracts with RAPD-PCR technique.

Of 42 random primers tested, only ten primers yielded informative data.

Primers O2, O10, Z10 and Z20 gave a number of bands that could be used as positive or negative molecular markers.

Primer O2 exhibited a band with 5905bp which appeared in the drought tolerant parental line (L3) and the tolerant F2 population but absent in all other genotypes.

Hence, it seemed to be a positive DNA-RAPD marker for drought tolerance in faba bean.

Primer O10 exhibited 3 bands with molecular size 1471bp, 1186bp and 977bp which were detected in the drought sensitive genotypes.

Hence, they seemed to be negative DNA-RAPD markers for drought tolerance.

Primer Z10 exhibited a band with molecular size of 1718bp only in L8, F2S and G716 which seemed to be sensitive for the aimed abiotic stress but it was absent in all other genotypes studied.

Consequently, it is considered as a negative molecular marker for drought tolerance.

The resulted dendrogram revealed three different genetic clusters.

The first cluster includes the four genotypes ; L3, F1, G461 and F2T.The second cluster includes the two drought sensitive genotypes ; G716 and F2S.

The third cluster comprises the sensitive parental line L8.The results generated from SDS–protein and DNA-RAPD profiles employed in the present investigation were pooled for drawing the genetic relationships among the seven faba bean genotypes tested.

The use of RAPD markers appears to be a good choice for assessing genetic relationships than SDS–protein in faba bean with polymorphism levels sufficiently high to establish informative fingerprints.

The primer OPZ3 was the most useful primer for identifying the tested genotypes.