Combining ability analysis for within-boll yield components in upland cotton (Gossypium hirsutum L.).

Cotton is an important cash crop worldwide, accounting for a large percentage of world agricultural exports; however, yield per acre is still poor in many countries, including Pakistan. Diallel mating system was used to identify parents for improving within-boll yield and fiber quality parameters. Combining ability analysis was employed to obtain suitable parents for this purpose. The parental genotypes CP-15/2, NIAB Krishma, CIM-482, MS-39, and S-12 were crossed in complete diallel mating under green house conditions during 2009. The F0 seed of 20 hybrids and five parents were planted in the field in randomized complete block design with three replications during 2010. There were highly significant differences among all F1 hybrids and their parents. Specific combining ability (SCA) variance was greater than general combining ability (GCA) variance for bolls per plant (9.987), seeds per boll (0.635), seed density (5.672), lint per seed (4.174), boll size (3.69), seed cotton yield (0.315), and lint percentage (0.470), showing predominance of non-additive genes; while seed volume (3.84) was controlled by additive gene action based on maximum GCA variance. Cultivar MS-39 was found to be the best general combiner for seed volume (0.102), seeds per boll (0.448), and lint per seed (0.038) and its utilization produced valuable hybrids, including MS-39 x NIAB Krishma and MS-39 x S-12. The parental line CIM-482 had high GCA effects for boll size (0.33) and seeds per boll (0.90). It also showed good SCA with S-12 and NIAB Krishma for bolls per plant, with CP- 15/2 for boll size, and with MS-39 for seeds per boll. The hybrids, namely, CP-15/2 x NIAB Krishma, NIAB Krishma x S-12, NIAB Krishma x CIM-482, MS-39 x NIAB Krishma, MS-39 x CP-15/2, and S-12 x MS-39 showed promising results. Correlation analysis revealed that seed cotton yield showed significant positive correlation with bolls per plant, boll size and seeds per boll while it showed negative correlation with lint percentage and lint per seed. Seed volume showed significant negative correlation with seed density. Seeds per boll were positively correlated with boll size and negatively correlated with bolls per plant lint percentage and lint per seed. Similarly, lint per seed exhibited positive correlation with lint percentage and boll size showed significantly negative correlation with bolls per plant. Presence of non-additive genetic effects in traits like bolls per plant, seeds per boll, lint per seed, seed cotton yield, and lint percentage is indicative of later generation selection or heterosis breeding may be adopted. For boll size, seed volume and seed density early generation selection may be followed because of the presence of additive gene action. The parental material used in this study and cross combinations obtained from these parents may be exploited in future breeding endeavors.

Genetic analysis of NaCl tolerance in tomato.

We attempted to find the suitable parents for the development of tomato hybrids for high salt soils by exploiting combining ability, gene action and heterosis. Six salt-tolerant and three salt-intolerant genotypes, along with their 18 F1 crosses, were evaluated at seedling stage under 10 and 15 dS/m (NaCl) salinity stress, compared to the control level of salinity. The experiment was laid out based on a two-way complete randomized design factorial arrangement with two replications; data on root and shoot length, fresh and dry weights, leaf area, plant length, Na(+), K(+) and K(+)/Na(+) concentrations were recorded. There was significant variation within genotypes, lines, testers, crosses, and line × tester interaction for all plant characters studied under normal and two salinity levels. Estimates of combining ability indicated that under low (10 dS/m) and high (15 dS/m) salinities, line BL1176 and tester LO2875 showed significant GCA effects for most of the traits studied. The cross-combinations 6233 × LO2875, CLN2498A x LO2875 and BL1176 × 17902 showed highest SCA values for most of the characters under 10 and 15 dS/m, respectively. Potence ratio showed that under low and high salinities, all the traits showed over dominant type of gene action except leaf area and K(+) concentration (in 10 dS/m) and shoot length, and leaf area (in 15 dS/m). The highest heterosis for most of the parameters was observed in cross-combinations BL1176 × LO2875 and CLN2498A x LO2875.

Genetic variability of NaCl tolerance in tomato.

Cultivation of crops in soils with high salt (NaCl) content can affect plant development. We examined the morphological and physiological mechanisms of salt tolerance in tomato. The responses of 72 accessions of tomato (Solanum lycopersicum) to salinity were compared by measuring shoot and root lengths, and fresh shoot and root weights relative to those of controls (plants grown in normal salt levels). All traits were reduced at the seedling stage when salinity levels were increased. The accession x salinity interaction was significant for all traits. Root length had higher heritability than other traits and was used as a selection criterion to identify salt-tolerant and -non-tolerant accessions. On the basis of root length, accessions LA2661, CLN2498A, CLN1621L, BL1176, 6233, and 17870 were considered to be more tolerant than accessions 17902, LO2875 and LO4360. The degree of salt tolerance was checked by analyzing K+ and Na+ concentrations and K+/Na+ ratio in tissues of plants treated with 10 and 15 dS/m salinity levels. Tolerance of these accessions to salinity was most associated with low accumulation of Na+ and higher K+/Na+ ratios.

Cerebral fungal infection with mycotic aneurysm of basilar artery and subarachnoid haemorrhage.

A 28-year-old Pakistani man was admitted with unresolved severe headaches for the past four weeks. Magnetic resonance (MR) imaging and MR angiography showed an enhancing mass in the sphenoid sinus, bilateral cerebellar infarcts and aneurysmal dilatation of the basilar artery. The differential diagnosis included fungal infection versus neoplastic lesion. The scrappings taken through the endoscope from the sphenoid sinus were initially negative for fungal infection. However, the second biopsy, done after putting him on antifungal, itraconazole 200 mg twice daily, revealed the presence of a fungal infection (aspergillosis). MR imaging revealed extension of the fungal infection from the sphenoid sinus into the clivus, and then intracranially. Imaging also revealed aneurysmal dilatation of the basilar artery and infarctions in the cerebellum and subarachnoid haemorrhage. Despite aggressive antifungal treatment, the patient died after 29 days. This case report describes the probable mechanism of fungal mycotic aneurysmal vascular dilatation and growth. It also points to the need for a rapid diagnosis of potential cases and an aggressive treatment approach of confirmed cases of fungal infections of the central nervous system.