Isolation of mitochondrial DNA sequences that distinguish male-sterility-inducing cytoplasms in Sorghum bicolor (L.) Moench

Abstract

We have demonstrated that sorghum DNA sequences of mitochondrial origin can be used to distinguish different male-sterility-inducing cytoplasms. Six DNA clones containing single-copy mitochondrial sequences were hybridized on Southern blots to restriction enzyme-digested DNA of 28 sorghum lines representing sources of different cytoplasmic male-sterility (CMS) groups. Four cytoplasmic types were defined on the basis of the pattern of DNA fragments detected. Similar analyses of 50 additional diverse sorghum accessions suggested that three of the four cytoplasmic types may be diagnostic for CMS. Also, three other cytoplasmic types were discovered. These and other mitochondrial DNA clones may be useful molecular tools for "fingerprinting" sterility-inducing cytoplasms in breeding programs, determining cytoplasmic diversity among germ plasm accessions, and identifying new sources of cytoplasm that induce male sterility.

Development and mapping of AFLP markers linked to the sorghum fertility restorer gene rf4

“…There are at least 22 sources of CMS in sorghum (Schertz et al 1989), which have been assigned to several groups (Pring et al 1995;Xu et al 1995). There are at least 22 sources of CMS in sorghum (Schertz et al 1989), which have been assigned to several groups (Pring et al 1995;Xu et al 1995).…”

Inheritance and molecular mapping of Rf6 locus with pollen fertility restoration ability on A1 and A2 cytoplasms in sorghum

“…In this direction, several non-milo CMS systems viz., A 2 , A 3 , A 4 , Indian A 4 (A 4 M, A 4 VZM, A 4 G), A 5 , A 6 , 9E and KS were described in sorghum [5][6][7][8][9][10][11]. Molecular characterization of cytoplasms using mitochondrial DNA probes indicated availability of sufficient diversity [12,13] to broaden the cytoplasmic base of sorghum hybrids. Despite the availability of diverse alternate CMS systems, hybrid vigor is exploited mainly using milo (A 1 ) cytoplasm.…”

Recent Advances in Sorghum Genetic Enhancement Research at ICRISAT

“…Availability of cytoplasmic-nuclear male sterility (CMS) system, higher heterosis % in the improved hybrids, and strong private sector presence facilitated the development of improved hybrids in large part of the globe. In addition to the widely used Milo-cytoplasm (A 1 ), cytoplasmic male-sterile lines are also available in A 2 , A 3 , A 4 , A 4 M, A 4 VZM, A 4 G1, A 5 , A 6 , 9E and KS cytoplasms [17][18][19][20][21][22][23]. Considering the restoration frequency, hybrid performance and comparable A 1 and A 2 CMS effects for grain yield and resistance to shoot fly and grain mold, it is advantageous to use A 2 CMS system for developing hybrid parents, among the alternate cytoplasms available.…”