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Navabi, A., Iqbal, M., Strenzke, K. and Spaner, D. 2006. The relationship between lodging and plant height in a diverse wheat population. Can. J. Plant Sci. 86: 723-726. We examined the genetic variation for lodging tolerance in different plant height groups, within a diverse population of wheat (Triticum aestivum L.) genotypes (n = 140). Lodging was artificially induced by dragging a weighted apparatus across plots twice during the season at early and late milk stages. Grain yield was negatively correlated with lodging, while lodging scores were positively correlated with plant height. Although plant height appeared to be the major contributor to lodging tolerance, some variation was also observed in taller plants. This suggests that genetic gain in lodging tolerance can be obtained, to some extent, independent of plant height.Key words: Plant height, lodging tolerance, Triticum aestivum L., CIMMYT, Canada Navabi, A., Iqbal, M., Strenzke, K. et Spaner, D. 2006. Lien entre la verse et la taille du plant dans un peuplement de blé mixte. Can. J. Plant Sci. 86: 723-726. Les auteurs ont examiné la variation génétique de la tolérance à la verse dans des groupes de taille différente au sein d'un peuplement de plusieurs génotypes (n = 140) de blé (Triticum aestivum L.). Ils ont induit artificiellement la verse en traînant un dispositif lesté de poids à deux reprises sur la parcelle, au début et à la fin du stade du grain laiteux. Le rendement grainier présente une corrélation négative avec la verse tandis que le degré de verse est positivement corrélé à la hauteur du plant. Bien que la taille du plant semble être le principal facteur concourant à la tolérance à la verse, on observe une certaine variation chez les plants les plus grands. On en déduit que la résistance à la verse pourrait être améliorée dans une certaine mesure par la génétique, peu importe la taille du plant. Mots clés:Taille du plant, tolérance à la verse, Triticum aestivum L., CIMMYT, Canada Lodging in cereals refers to the displacement of culms from an upright position. Lodging is often associated with yield loss, with the magnitude of loss dependent on cultivar, growth stage, and the severity of lodging (Fischer and Stapper 1987;Jedel and Helm 1991;Kelbert et al. 2004a). Height reducing (Rht) genes are the major sources of lodging tolerance in wheat (Triticum aestivum L.). However, reduced plant height may not always be suitable for all agro-econiches. For example, in organically managed wheat systems, a relatively taller plant with greater tillering capacity may potentially confer increased competitive ability (Spaner, unpublished data). Sources of lodging tolerance independent of height reducing genes may be of interest to plant breeders selecting for competitive ability within taller genotypes.In previous studies (Kelbert et al. 2004a) we reported the artificial induction of lodging by dragging a weighted plywood apparatus over experimental wheat plots. This technique was originally proposed by Briggs (1990) as a screening tool for lodging tol...

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Genome-wide association study (GWAS) was performed for stomata- and yield-related attributes with high-density Illumina 90 K Infinium SNP (single nucleotide polymorphism) array in bread wheat to determine genetic potential of germplasm for scarce water resources with sustainable yield potential. Major yield and stomata attributes were phenotyped on a panel of Pakistani and foreign accessions grown in non-stressed and water shortage environments during two seasons. Highly significant variations were shown among accessions in both conditions for examined characteristics. Water shortage conditions reduced the overall wheat yield and strong positive correlation existed among stomatal frequency, leaf venation and grain yield per plant. Population structure analyses based on 90,000 SNP data classified the accessions into four sub-populations which indicated the presence of genetic variability. Marker-trait association (MTA) analyses revealed that 422 significant SNPs at p ≤ 10−3, after crossing the false discovery rate (FDR) <0.05 threshold, were linked with examined attributes. Pleiotropic loci (wsnp_Ex_c8913_14881924 and Tdurum_contig10598_304) were associated with flag leaf area (FLA), stomata size (SS), stomata frequency (SF), leaf venation (LV), number of grain per spike (NGS) and grain yield per plant (GYP), which were located on chromosome 4B and 6B at the positions 173.63cM and 229.64cM, respectively, under water shortage conditions. Pleotropic loci wsnp_Ex_c24167_33416760, wsnp_Ex_c5412_9564046 and Tdurum_contig81797_369 on chromosomes 7A, 2A and 4B at the positions 148.26cM, 261.05cM and 173.63cM, respectively, were significantly linked with stomata and yield indices such as FLA, SS, SF, LV, NGS and GYP under normal and water shortage conditions. The current experiment not only validated several MTAs for studied indices reported in other studies but also discovered novel MTAs significant under water shortage environments. Associated and significant SNPs will be useful in discovering novel genes underpinning water shortage tolerance in bread wheat for producing high-yielding and drought tolerant wheat varieties to fulfill the wheat demand for growing populations.

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FBPase deficiency is often fatal in the infancy and early childhood. Early diagnosis and prompt treatment is therefore crucial to preventing early mortality. We recommend the use of c.472C>T and c.841G>A mutations as first choice genetic markers for molecular diagnosis of FBPase deficiency in Pakistan.

Cotton growers face a problem of low cotton yield in late planting (after sunflower and maize). The objective of our study was to determine the effects of planting date, plant spacing (plant density), and genotypes on seed cotton yield and its components, ginning outturn (GOT%), and fiber quality traits (fiber length and fiber fineness). Five planting dates (May 1, May 15, May 30, June 15, and June 30), three plant spacings (15, 30, and 45 cm), and three cotton genotypes (CRS-6070, CRS-738, and CIM-496) were evaluated for seed cotton yield with its components and fiber quality traits. The results showed that monopodial branches/plant, sympodial branches/plant, number of bolls/plant, and seed cotton yield differed significantly among different planting dates, plant spacing, and genotypes. While the boll weight was significantly different among genotypes only. GOT%, fiber length, and fiber fineness were different significantly among planting time and cotton genotypes, which were not significantly affected by plant spacing. Cotton grown in early planting dates had higher seed cotton yield (4874 and 4653 kg/hm 2 ) at the highest plant spacing (45 cm). While late sown cotton (June 15 onward) gave higher seed cotton yields (2068 and 1889 kg/hm 2 ) at the lowest plant spacing (15 cm). GOT%, fiber length, and fiber fineness improved significantly in late planting and not affected from plant spacing. From our present study, it is concluded that high seed cotton yield can be achieved at high plant spacing in early planting while at low plant spacing in late planting.

Biosafety of a genetically modified crop is required to be assessed prior to its commercialization. For this, a suitable artificial diet was developed and used to establish a dietary exposure test for assessing the toxicity of midgut-active Bt insecticidal proteins on Chrysopa pallens (Rambur). Subsequently, this dietary exposure test was used to evaluate the toxicity of the proteins Cry1Ab, Cry1Ac, Cry1Ah, Cry1Ca, Cry1F, Cry2Aa, Cry2Ab, and Vip3Aa on C. pallens larvae. Temporal stability, bioactivity, and the intake of the insecticidal proteins were confirmed by enzyme-linked immunosorbent assay and a sensitive-insect bioassay. The life history characteristics, such as survival, pupation, adult emergence, 7-day larval weight, larval developmental time, and emerged male and female fresh weights remained unaffected, when C. pallens were fed the pure artificial diet (negative control) and the artificial diets containing 200 μg/g of each purified protein: Cry1Ab, Cry1Ac, Cry1Ah, Cry1Ca, Cry1F, Cry2Aa, Cry2Ab, or Vip3Aa. On the contrary, all of the life history characteristics of C. pallens larvae were adversely affected when fed artificial diet containing boric acid (positive control). The results demonstrate that diets containing the tested concentrations of Cry1Ab, Cry1Ac, Cry1Ah, Cry1Ca, Cry1F, Cry2Aa, Cry2Ab, and Vip3Aa have null effects on C. pallens larvae. The outcome indicates that genetically modified crops expressing the tested Bt proteins are safe for the lacewing, C. pallens.