Evaluation of new inbreds for fertility restoring and maintaining behaviours in two diverse CMS sources of sunflower (Helianthus annuus L.).

Abstract

Eight cytoplasmic male sterile (CMS) lines of sunflower (Helianthus annuus L.) belonging to two different sources of cytoplasmic male sterility, PET-1 (H. petiolaris) (CMS-852A, CMS-7-1A, CMS-234A, CMS-2A, COSF-1A, COSF-7A and CMS-10A) and CMS I (H. lenticularis) (IMS-852A) were crossed with newly developed 20 inbred lines to identify the maintainer or restorer behaviour in Line x Tester fashion and evaluation of test cross progenies was conducted at the Narkhoda farm of Indian Institute of Oilseeds Research, Rajendranagar, Hyderabad in a randomized block design replicated twice. The presence or absence of pollen in F1s was recorded in the field whereas pollen fertility was confirmed in the laboratory by Acetocarmine staining test. All the inbreds were categorized into complete restorer, partial or week restorer and maintainer through cytological observation. 12 inbreds viz., RHAGKVK-1, RHAGKVK-2, AKSFI-49-3, AKSFI-49-4, AKSFI-46-2, HOHAL-37, CSFI-5134, CSFI-5055, CSFI-5133, CSFI-5185, CSFI-5075 and Selection-I were restored fertility to most of the PET-1 CMS lines. While, CSFI-5033, IB0-50, IB-60, IB-61, IB-67 and IB-101 inbreds were maintained sterility. The second CMS line IMS-852A, was maintained by thirteen inbreds indicating involvement of different gene(s). Only one inbred CSFI-5134 was restored its fertility. Some of the inbreds (AKSFI-49-3 & AKSFI-49-4) were behaved as partial restorers for CMS-10A. Restoration/maintenance patterns indicated that at least some restorer genes are specific to certain CMS. The range of fertility restoration in different cross combinations was between 46.6 and 99.5 per cent. In the present study 50 to 65% frequency of pollen fertility was reported for PET-1. However, only 5 percent frequency of pollen fertility was observed for CMS I. From the study it was evident that among the two CMS sources, restorers for CMS I are rather scarce. Efforts should be made to locate restorers for CMS I for its utilization in production of more productive sunflower hybrids.