| A cytoplasmic male sterile (cms) line GDS in Maize(Zea mays) and its maintainer BG were selected from segregation of self-pollination. This study focused on the following points: a) characteristics of GDS in growth, cytoplasm type via a Polymerase Chain Reaction (PCR) protocol, cytological property, and disease resistance; b) restorer and its genetic background and FI fertility stability; and c) various types of GDS restorers via a Random Amplified Polymorphic DNA (RAPD). Simultaneously, responses of various cms types (cms-T, -C, and -S) to restorers from different backgrounds were investigated, which could be important to utilize cms in seed production and provided new methods and guidelines for selecting suitable restorers. The main conclusions can be summarized as follows. 1. Characteristics of male sterile line1.1 Stability of male sterilityMale sterile lines GDS and GDS(478) were stable across testing seasons and locations. This indicated that this kind of male sterility was independent of environment condition, e.g., temperature and light.1.2 Configuration aspectsAmong various conditions, tassel and anthers from cms lines GDS and GDS(478) were closed during maturity. The length of anther from cms line GDS was 58% of that from normal line (maintainer). There is no pollen in most of anthers.1.3 Tassel growthThe differences in main axis length, spikelets per main axis, branches, and total spikelets were marginal between cms lines GDS, GDS(478) and their maintainers. These parameters did varied with growing seasons. Tassel branches were much less in winter at Sanya than in spring and autumn at Changsha.1.4 Photosynthesis ratePhotosynthesis rate was monitored at three main stages, most of which were higher in cms lines GDS and GDS(478) than their maintainers. The highest photosynthesis rate was detected at silking (tasselling) period as 33.91, 33.85, 32.22, and 3Q.26umol-m~2-s~l for GDS(478), 478, GDS, and BG lines, respectively.2. Discrimination of GDS male sterile type2.1 Field observationGDS, GDS(478), and other 11 cms (5 cms-T, 2 cms-C, and 4 cms-S) lines as CK were tested for their fertile behavior. Except C836D (S) and C836H (S), all other lines were male sterile in both Sanya and Changsha over seasons.2.2 Restorers for GDS and its deduced male sterile typeBoth lines C936D (RfiRfiRf2Rf2 rf3rf3 RfCRfC) and C936F (rfirf1Rf2Rf2rf3rf3RfCRfC) could restore GDS and GDS(478), while C736CB (RfiRfiRf2Rf2) and C936K (RfiRfiRf2Rf2) could not do. It is deduced that GDS and GDS(478) were grouped into cms-C type.2.3 Discrimination of male sterile type from a rapid PCR procedureUsing 3 pairs of specific primers, GDS, GDS(478),B37-N(Normal), B37-T(cms-T), B37-C(cms-C), and B73-S(cms-S) were tested via a PCR protocol. There were similar bands from GDS and GDS(478) lines as B73-C. Thus, GDS and GDS(478) should be cms-C type, which is consistent with the test from specific restorers.3. Cytological characteristic and disease resistance3.1 Characteristics of microspore abortion in male sterile GDSMicrospore abortion happened relatively early in male sterile GDS, shown in early stages of microspore maternal cell meiosis. This means, microspore maternal cell failed to meiosis. There were two types of abortion, i.e., a) fine layers expanding abnormally and microspore maternal cells condensing to disjoint and b) fine layers vacuolifing to a very low extent and maternal cells in pollens beginning to condense and disjoint. There is no report for the second type up to now.3.2 Disease resistanceWith manual inoculation pathogen, cms GDS line was highly insensitive to Nothern blight of corn, but both cms line CDS and its maintainer BG were similar reaction to Southern blight of corn.4. Restorer for cms CDS4.1 Natural selecting restorerFrom segregation of M sterile plant which was in natural cross-pollination, the fertile plants were selected and self-pollinated continuously. Four lines, named as H53, H54, H57, and H58 were obtained for restoring GDS.4.2 Compa...
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