African Journal of Crop Science

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (12), pp. 001-009, December, 2018. © International Scholars Journals

Full Length Research Paper

Effects of variety and row spacing on radiation interception, partitioning of dry matter and seed set efficiency in late season sunflower (Helianthus annuus L.) in a humid zone of Nigeria

Agele, S. O. ^1*, Maraiyesa, I. O.² and Adeniji, I. A²

¹Department of Crop, Soil and Pest Management, Federal University of Technology, Akure, Nigeria.

²ARMREC, University of Agriculture, Abeokuta, Nigeria.

Accepted 25 May, 2018

Abstract

In the tropics, crops sown in the late season are subjected to concurrent stresses of high air and soil temperatures, large saturation vapour pressure deficits and negligible soil water regimes. The responses of three sunflower cultivars to row spacing was analysed in terms of radiation interception and use, plant to plant variability, biomass accumulation and seed set efficiency during the late seasons of 2002 and 2003 on the field in Akure, a rainforest zone of Nigeria. Sunflower cultivars (Functua local, Record and Isaanka) were cropped at 90 x 30, 90 x 60 and 60 x 30 cm row spacing corresponding to 37,037, 18,519 and 55,555 plant.m^-2 Increasing density of plant stand appeared to have promoted differences in resource availability per plant during growing season. Row spacing did not significantly affect IPAR while the effects of spacing and cultivar were similar on RUE. Leaf area and dry matter accumulation are suboptimal but RUE appeared to be conservative in circumstances of high saturation vapour pressure deficit and soil moisture stress of the late season. Crops in wide rows intercepted less radiation than their counterparts in narrow rows, and yield response to narrow rows was significant in all cultivars. Seed yield/ha increased as plant density increased although yield of the individual plants and their components were significantly reduced. Among the cultivars, differences in the growth of individual plant at different intensities of inter plant competition were obtained, narrow row spacing enhanced plant-plant variability (inter-plant variation). Under the limiting soil water situation enhanced soil temperatures of the late season EF relates to plant biomass (r² > 0.70), dry matter relates to accumulated intercepted radiation IPAR (r² > 0.90) and fractional intercepted radiation (fIPAR) relates to seed yield (r² > 0.95) while fIPAR is a function of thermal time (TT) (r² > 0.80).

Key words: Sunflower, cultivars, late season, RUE, extinction coefficient, plant-plant variability, dry matter partitioning, seed set, seed yield.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (12), pp. 001-007, December, 2018. © International Scholars Journals

Full Length Research Paper

Identification of coupling- and repulsion-phase markers in rice for brown planthopper resistance genes using F₂S of IR 50 X CO 46

Venkateswarlu Yadavalli^1,2*, Gajendra P. Narwane², P. Nagarajan² and M. Bharathi³

¹Department of Biochemistry, School of Life Sciences, University of Hyderabad. Hyderabad (AP), India-500 046, India.

²Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamilnadu, India-641003, India.

³Department of Entomology, Tamil Nadu Agricultural University, Coimbatore, Tamilnadu, India-641003, India.

Accepted 22 July, 2018

Abstract

Brown planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae) is one of the most threatening pests, often significantly reducing the rice yield. The breeding of resistant cultivar has been the most effective way of controlling this pest. Recent advancements in DNA marker technology together with the concept of marker-assisted selection (MAS) provide new solutions for selection of more durable brown planthopper (BPH) resistant genotypes in rice. F₂s of a cross between IR 50 and CO 46 and their susceptible and resistant parents were used for the present study. In bulk segregant analysis, random amplification of polymorphic DNA (RAPD) primer, OPC 11 (5’AAAGCTGCGG 3’) showed co-dominant banding pattern, which amplified a susceptible phenotype specific marker OPC11₈₅₆ associated with repulsion phase_. It also amplified resistant phenotype specific markers, OPC 11₈₁₇ which are associated in coupling phase to the resistant allele. The OPA11₈₁₇ RAPD marker could be used in a cost effective way for marker assisted selection of BPH resistant rice genotypes.

Key words: RAPD markers, brown planthopper, bulk segregant analysis, hopper burn, Oryza sativa.

African Journal of Crop Science ISSN 2375-1231 Vol. 6 (11), pp. 001-007, November, 2018. © International Scholars Journals

Full Length Research Paper

Adaptation of Moroccan durum wheat varieties from different breeding eras

Nasserlehaq Nsarellah¹, Ali Amamou¹*, Mouna Taghouti¹ and Paolo Annicchiarico²

¹Institut National de la Recherche Agronomique, B.P 589, Settat, Morocco.

²Research Institute Lodi, Italy.

Accepted 12 March, 2018

Abstract

The continuous technological and environmental changes are reasons for periodical re-evaluation of variety performances and adaptation. The objective of this work was to re-assess the adaptation of the main registered durum wheat (Triticum turgidum var. L. durum) varieties in Morocco. Twenty three varieties were tested in six sites and during four consecutive growing seasons 2001 to 2005. The experimental layout was a randomized complete block design trials of three replicates. Two methods of genotype by environment interaction analysis were performed and results were compared: the regression model and the additive main effects and multiplicative interaction model (AMMI). Analysis of variance showed highly significant effects of the experiment sites, the cropping seasons and of the varieties. Significant interactions of these main effects were also shown. Specific adaptation of particular varieties to specific sites was hence demonstrated. The conclusions brought by the two methods were concordant in rating the new Hessian fly resistant varieties as adapted to the dry lands and in rating the remaining high-yielding varieties as adapted to the favorable areas. AMMI analysis first component of variation explained 60.4% of error sum of squares due to genotype by location interaction while the regression model only explained 37.7 % of that same error.

Key words: Triticum turgidum var. ‘durum’, environment, GxE interaction, adaptation, regression, AMMI.