Genetic improvement of salt tolerance is of high importance due to the extent and the constant increase in salt affected areas. Sorghum [Sorghum bicolor (L.) Moench] has been considered relatively more salt tolerant than maize and has the potential as a grain and fodder crop for salt affected areas. One hundred sorghum genotypes were screened for salinity tolerance in pots containing Alfisol and initially irrigated with a 250-mM NaCl solution in a randomized block design with three replications. Subsequently 46 selected genotypes were assessed in a second trial to confirm their responses to salinity. Substantial variation in shoot biomass ratio was identified among the genotypes. The performance of genotypes was consistent across experiments. Seven salinity tolerant and ten salinity sensitive genotypes are reported. Relative shoot lengths of seedlings were genetically correlated to the shoot biomass ratios at all stages of sampling though the relationships were not close enough to use the trait as a selection criterion. In general, the whole-plant tolerance to salinity resulted in reduced shoot Na + concentration. The K + /Na + and Ca 2+ /Na + ratios were also positively related to tolerance but with a lesser r 2 . Therefore, it is concluded that genotypic diversity exists for salt tolerance biomass production and that Na + exclusion from the shoot may be a major mechanism involved in that tolerance.

In the semi-arid tropics, over two-third's of the world's people depend on agriculture within which livestock play a major role in building rural livelihoods. Crop residues (fodder/stover) are important feed resources for ruminants. This review was undertaken with the objective of improving understanding of the role of various crop management factors in affecting the productivity and quality of crop residues. Variability in productivity and quality of residues can be of both genetic and nongenetic origin. Recommended agronomic practices vary according to crop and cultivar and can release the maximum genetic potential determining quantity and quality of residues. Planting method and planting rate recommendations should be followed to maximise productivity. Although low density planting improved fodder quality, fodder yield declined. Time of sowing affected fodder yield in most of the crops, but fodder quality was not generally affected. It was common to observe that application of nitrogen (up to 120 kg ha À1 ) in cereals and application of phosphorus (up to 60 kg ha À1 ) in legumes improved the green and dry fodder yields, as well as crude protein (CP), crude fibre (CF) and other quality parameters. Inoculation of cereal seed with nitrogen fixing bacteria such as Azotobacter and seed of pulses with phosphate solubilising bacteria has been reported to decrease fertiliser needs and improve the CP and in vitro dry matter digestibility (IVDMD) of fodder. Irrigating at more frequent intervals by splitting the same quantity of irrigation water into smaller irrigations and at critical stages improved dry matter and CP yields. Hand weeding resulted in better weed control efficiency and stover yield than application of herbicides. However, application of herbicides resulted in the greatest benefit:cost ratio. Manual harvesting resulted in lower losses than mechanical harvesting, and may affect quality depending on the extent of loss of different fodder components. Drought stress yielded more digestible organic matter due to increases in the proportion of leaves compared to stems. Saline conditions affected seed germination and crop yields. Several methods are suggested to counteract the effects of salinity. Intercropping of cereals with legumes improved fodder nutritional quality (mostly protein content). In almost all crops, a positive association was found between fodder and grain yield indicating simultaneous improvement in both characters. In most cases, fodder yield and digestibility were positively correlated and showed positive association with plant height, leaf number and the number of tillers per plant, but there were limits and variation among crops.The ICRISAT-ILRI partnership experiments were conducted with a diverse set of sorghum and pearl millet cultivars at ICRISAT, India. Planting density levels in both crops did not influence forage quality although some fodder yield traits were affected. A significant interaction of genotype with planting density was observed for grain and fodder yield in sorg...

Six malcsterlle plantr, found in two a p arently u n r c laced murca In lgron pea (Cajanur c a l m L) Huth) did not produce poylen. Crouln sucteu was normal, Indl. tatlng that the Iaats were ?rmalcfertllc. White Uanc lucent anthcr co& dlstln lshed m a l~t e r i l e plan" from ferclle plants, which h a y yellowirh anthm. A sin lc rcceu~ve allele was r a nrlble for the male stcri~ity 8c. &bed hcre, Study o r m l c r w men18 revealed that tetrads in male amilc lants uparate and they c m p l a e l y dlsintegratcdj The ta a u m and the inter. cellular wall of the two ad scent mfccmrpnndn pmirted in the mature anthem. jrhc potential value of male aterlllty In breeding propanu 11 Mlcated.

The overall objective of this work was to investigate variation in grain yield (GY), stover yield (SY), fodder quality of stover and their association in sorghum and pearl millet. These relationships were investigated in India in 12 genotypes of sorghum and six genotypes of pearl millet grown under high fertilizer (HF) and low fertilizer (LF) application. Fodder quality of stover was assessed by digestibility and intake measurements in bulls. In sorghum, highly significant genotype-dependent variation was found for GY, SY and fodder value of stover regardless of level of fertilizer application. GY and fodder quality of stover were not inversely related and the genotype with the highest GY, for example, had also the best fodder quality in the stover. High GY and high fodder quality in sorghum stover seem to be compatible traits. In pearl millet, genotypic variation in GY and SY and quality was expressed under HF but not under LF application. No consistent significant genotypic differences were found for fodder quality measurements in pearl millet except for cell wall digestibility. Digestible organic matter intake (DOMI) when bulls were fed to appetite was considered the crucial determinant of stover quality in sorghum and pearl millet. Live weight changes in bulls estimated by DOMI varied genotype-dependently from À140 to þ100 g per day in 300 kg bulls. However, this paper argues that genotypes promoting high DOMI are only suitable for farmers with sufficient amounts of stover to allow the feeding of animals to appetite. Farmers with restricted amounts of stover are better served by genotypes that promote high digestibility under restricted feed intake. #

Effective greenhouse-and field-screening techniques were developed to identify resistance to anthracnose (Cc!' minicola) in grain sorghum (Sorghum bicolor). In greenhouse screening, sorghum plants were spray-innnl!s;-1: with a conidial suspension ( 4 X lo5 conidia ml -' ) of C. graminicola. Inoculated plants were iacch-:-chamber ( 3 90% RH) for 24 h at 25-28'C and relocated to a greenhouse at 25 f. 2°C. Anthracnose devalc,, 8 days after inoculation. In the field-screening technique. in every fifth row, a highly anthracnose-si.=;:i:it sown as an infector row. Ten days later, test lines were sown between infector rows, and infector row d at the 6-8 leaf stage with either spore suspension or by dropping infected sorghum grains into the leaf -: was provided by frequent overhead sprinkler or furrow irrigation. Test lines were scored for anthracnose 1 :. t the hard-dough stage. Significant positive correlation (r=0.88, P<0.001) was found for anthracnose sever!; eedling screening in greenhouse and adult plant screening in the field. The field-screening technique was successfully several locations in Africa and India. Thirty lines were selected from more than 13 000 sorghum germplasm i t c. vanced breeding lines screened for anthracnose resistance, using the field-screening technique at Pantnagar ( ?; I between 1982 and 199 1. They were evaluated in multilocational tests at hot spots in Burkina Faso, India, Nigeria.Zimbabwe for 1-10 years. Eleven lines (A 2267-2, IS 3547, IS 8283, IS 9146, IS 9249, IS 18758, SPV 386, PB : 18601-3, PM 20873-1-3, and M 35610) showed stable resistance across these locations over the years. Some of ; 18 lines are being converted into male-sterile lines through backcrossing with different sources of cytoplasmic male -r;

The spotted stem borer, Chilo partellus, is one of the most important pests of sorghum, and host plant resistance is an important component for the management of this pest. Most of the sorghum hybrids currently under cultivation are based on cytoplasmic male-sterility (CMS). In order to develop a strategy for resistance to stem borer, we studied the traits associated with resistance, and their nature of gene action in F 1 hybrids derived from resistant, moderately resistant, and susceptible CMS and restorer lines. The hybrids based on stem borerresistant, moderately resistant, or susceptible CMS and restorer lines were equally resistant or susceptible as the parents for leaf feeding [Damage rating (DR) 5.8 to 6.6 vs. 5.9 to 6.6], and had significant and decreasing trend in deadheart formation (resistant CMS · resistant restorer lines < moderately resistant CMS · moderately resistant restorer lines < susceptible CMS · susceptible restorer lines), respectively. Proportional contributions of restorer lines were greater than those of the CMS lines for leaf feeding, deadhearts, recovery and overall resistance, stalk length, nodes per plant, stem borer holes per plant, and peduncle tunneling. The general (GCA) and specific combining ability (SCA) estimates suggested that leaf feeding score, number of nodes, overall resistance score, panicle initiation, recovery score, and stalk length (dominance type of gene action) have been found to be associated with resistance to spotted stem borer, governed by additive type of gene action, their correlation and direct effects in the same direction, and explained 65.3% of the variation in deadhearts, and thus could be used as marker traits to select and breed for resistance to C. partellus in sorghum. The parents having significant SCA effects for two or more resistance traits for either or more parents have also been discussed for their use in the stem borer resistance breeding.

The shoot fly, Atherigona soccata is an important pest of sorghum, and host plant resistance is one of the most effective components for managing this pest. Most of the hybrids grown in India based on milo cytoplasm (A 1 cytoplasm) are highly susceptible to shoot fly. Therefore, the present studies were undertaken to evaluate different male-sterile cytoplasms (CMS) for their relative susceptibility to sorghum shoot fly. Oviposition and deadheart formation were significantly lower on the maintainer lines as compared to the corresponding male-sterile lines. Among the cytoplasms tested, A 4 M cytoplasm showed antixenosis for oviposition and suffered lower deadheart formation than the other cytoplasms tested. The A 4 G 1 and A 4 M cytoplasms suffered lower deadhearts in tillers than the other cytoplasms. Recovery following shoot fly damage in A 4 M, A 3 , and A 2 cytoplasms was better than in the other cytoplasms tested. The larval and pupal periods were longer and male and female pupal weights lower in A 4 M and A 4 VzM CMS backgrounds compared to the other CMS systems. Fecundity and antibiosis indices on CMS lines were lower than on the B-lines. The A 4 M cytoplasm was found to be relatively resistant to sorghum shoot fly, and can be exploited for developing shoot fly-resistant hybrids for sustainable crop production in future.

An investigation was carried out to assess the efficiency of A 2 cytoplasmic-nuclear male-sterility (CMS) system in comparison to the widely used A 1 cytoplasm in terms of general combining ability (gca) effects of male-sterile (A-) lines and mean performance, specific combining ability (sca) effects and mid-parent heterosis of hybrids for days to 50% flowering, plant height and grain yield at International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India in 2001 and 2002 rainy seasons. The material for the study consisted of six pairs of iso-nuclear, allo-plasmic (A 1 and A 2 ) A-lines and 36 iso-nuclear hybrids produced by crossing these A-lines with three dual restorer (R-) lines. The results revealed that cytoplasm and its first-order interaction with year, R-and A-lines did not appear to contribute to variation in isonuclear hybrids for plant height and grain yield. Cytoplasm had limited effect on gca effects of Alines and on sca effects and mid-parent heterosis of iso-nuclear hybrids for days to 50% flowering, plant height and grain yield. The mean days to 50% flowering, plant height and grain yield of A 2 cytoplasm-based hybrids were comparable with those of widely used A 1 cytoplasm-based hybrids. The relative frequency of the occurrence of the A 1 -and A 2 -based hybrids with significant sca effects and mid-parent heterosis indicated that A 2 CMS system is as efficient as A 1 with a slight edge over A 1 for commercial exploitation. The implications of these results are discussed in relation to opportunities for broadening not only cytoplasm base but also nuclear genetic base of both the hybrid parents.