Yield Improvement Programs Research Articles

Interactions between nitrogen nutrition, canopy architecture and photosynthesis in rice, assessed using high-resolution 3D reconstruction

AbstractIncreasing nitrogen use efficiency is a key target for yield improvement programs. Here we identify features of rice canopy architecture during altered N availability and link them to photosynthetic productivity. Empirical mathematical modelling, high-resolution 3-dimensional (3D) reconstruction and gas exchange measurements were employed to investigate the effect of a mild N deficiency vs. surplus N application on canopy architecture, light and photosynthesis distribution throughout development. Three contrasting rice lines: two Malaysian rice varieties (MR219 and MR253) and a high-yielding indica cultivar (IR64) were cultivated. 3D reconstruction indicated key N-dependent differences in plant architecture and canopy light distribution including changes to leaf area index (LAI), tiller number, leaf angle and modelled light extinction coefficients. Measured leaf photosynthetic capacity did not differ substantially between the high and reduced N treatments; however, modelled canopy photosynthesis rate indicated a higher carbon gain per unit leaf area for the reduced N treatment but a higher carbon gain per unit ground area for the high N treatment. This is a result of altered canopy structure leading to increased light distribution under reduced N which partially offsets the reduced LAI. Within rice, altered N availability results in the development of full photosynthetically functional leaves, but leads to altered canopy architecture, light distribution and overall productivity suggested that N availability can be fine-tuned to optimize biomass production. We propose wider use of 3D reconstruction to assess canopy architecture and productivity under differing N availabilities for a range of species.

Pyramiding of High Grain Weight With Stripe Rust and Leaf Rust Resistance in Elite Indian Wheat Cultivar Using a Combination of Marker Assisted and Phenotypic Selection.

Wheat (Triticum aestivum L.) is an important cereal crop globally as well as in India and yield improvement programs encounter a strong impediment from ever-evolving rust pathogens. Hence, durable rust resistance is always a priority trait for wheat breeders globally. Grain weight, represented as thousand grain weight (TGW), is the most important yield-contributing trait in wheat. In the present study high TGW has been transferred into two elite Indian wheat cultivars PBW343 and PBW550 from a high TGW genotype, Rye selection 111, selected from local germplasm. In the background of PBW343 and PBW550, an increase in TGW upto 27.34 and 18% was observed, respectively (with respect to recipient parents), through conventional backcross breeding with phenotypic selections in 3 years replicated RBD trials. Resistance to leaf rust and stripe rust has been incorporated in the high TGW version of PBW550 through marker assisted pyramiding of stripe rust resistance gene Yr15 using marker Xuhw302, and a pair of linked leaf rust and stripe rust resistance genes Lr57-Yr40 using marker Ta5DS-2754099_kasp23. Improved versions of PBW550 with increased TGW ranging from 45.0 to 46.2 g (up to a 9% increase) and stacked genes for stripe and leaf rust resistance have been developed. This study serves as proof of utilizing conventional breeding and phenotypic selection combined with modern marker assisted selection in improvement of important wheat cultivars as a symbiont of conventional and moderan techniques.

Gene action in low nitrogen tolerance and implication on maize grain yield and associated traits of some tropical maize populations

AbstractUnderstanding the mode of inheritance of traits is vital in the selection of breeding methods for the grain yield and improvement of associated traits in a target environment. Combining ability is one of the powerful indices for the selection of the best cross combinations, parental lines that combine with other lines and the best breeding method for high grain yield improvement programmes. A total of 45 crosses were generated from ten maize varieties developed in low nitrogen environment in a diallel mating fashion without reciprocal. The resultant progenies were investigated in low- and highnitrogen soil to identify the mode of grain yield inheritance and those of related traits in the tested environments. Mean square analysis revealed the preponderance of additive and non-additive gene actions in the expression of maize grain yield and related characters tested under stress and optimal conditions. In this study, it is proved that both standard selection and hybridization breeding strategies are effective for the improvement of most traits involved. This experiment also confirmed the adequacy of sufficient variation in the gene pool present in the maize population that could be exploited in maize grain yield improvement programmes in the tropics. The ratio of SCA to GCA however emphasized the superiority of additive gene effects in the expression of most traits in the tested environments. The results, therefore, suggest that additive gene actions primarily condition the expression of maize grain yield and associated characters in the tested environments. Therefore, suggesting that the standard selection method would be effective for the improvement of most traits tested under the two environments.

Estimation of genetic variation, heritability and genetic advance for yield and agronomic traits correlation of some low nitrogen tolerance maize (Zea mays) varieties in the tropics

Genetic improvement of a crop is highly depended on the abundance of genetic variation present within the crop populations. High genetic advance and high heritability estimates presents the most suitable condition for selection of which heritability estimate is employed by breeders in allocating resources necessary to effectively select for desired traits and to achieve maximum genetic gain with little time and resources. Based on this, ten open pollinated low nitrogen tolerance maize genotypes were tested during the cropping season of 2016 to 2017 at Teaching and Research farm, Landmark University, Kwara State, Nigeria to estimate the genetic variance, heritability, and expected genetic advance of 12 maize population for grain yield and its component characters. The 10 low N maize populations and 2 checks were evaluated under two different nitrogen regimes 90kg and 30kg of N/ha classified as high N and low N respectively. The study revealed lower phenotypic variances (σ2p) and PCVs relative to genetic variances (σ2g) and GCVs for all the studied characters, suggesting the low influence of environmental factors in the expression of these characters. High degree of genotypic coefficient and phenotypic coefficient of variance, heritability and genetic advance were recorded for grain yield, anthesis silk interval, husk cover, plant height, ear height, plant aspect, days to silking and days to pollen shed. Further, lowest value of interval between days to anthesis and silking was obtained by BR 9928-DMRSR LN C1. Highest maize grain yield was recorded by varieties TZLCOM1C6LNC I (6.19 t/ha) and Sint Marzocalarga (5.26 t/ha) under high N and low N respectively. These two maize genotypes can therefore be suggested for the future maize grain yield improvement programmes in low and high nitrogen soil condition in the tropic.

Correlation studies in magic indica plus population and Indian rice germplasm

One hundred and two MAGIC indica plus lines, one hundred and four rice accessions, along with four standard checks of rice (Oryza sativa L.) were evaluated during Kharif 2017 to study the nature and extent of correlation among yield and yield attributing characters viz., days to 50 per cent flowering, plant height, number of productive tillers per plant, panicle length, number of filled grains per panicle, number of grains per panicle, spikelet fertility, thousand-grain weight, grain yield per plant. The results revealed that grain yield plant per plant to be positively and significantly associated with with number of filled grains per panicle (rp= 0.657**; rg= 0.665), spikelet fertility (rp= 0.301**; rg= 0.321), number of productive tillers per hill (rp= 0.153**; rg= 0.068), panicle length (rp= 0.133**, rg= 0.114) indicating importance of these traits as selection criteria in yield improvement programmes.

Genetic variability, correlation and path analysis studies for yield and yield attributes in African rice (Oryza glaberrima) germplasm

Thirty-one accessions of Oryza glaberrima were evaluated to study variability, correlation and path analysis for yield and yield attributing traits. Three checks namely, BPT 5204, IR 64 and Swarna for were utilized for comparison of variability parameters. High range of variation, PCV, GCV and high heritability coupled with high genetic advance was observed for days to 50 per cent flowering and the number of spikelets per panicle. Correlation revealed that the number of productive tillers per plant, panicle length, spikelets per panicle, 1000 seed weight, kernel length, and L/B ratio showed a positive association with grain yield. However, days to 50% flowering, plant height and kernel breadth were found to be negatively correlated. Path analysis identified L/B ratio, panicle length and kernel breadth, which had the maximum direct positive effect on grain yield, while, L/B ratio via kernel length and days to 50% flowering via 1000 seed weight exhibited high positive indirect effects on grain yield per plant. Therefore, the selection of accessions with more panicle length and early maturity would be most suitable for selection in yield improvement programs.

Morphological and SSR Marker Based Diversity Analysis of Lentil (Lens esculenta) Genotypes using Yield and Yield Contributing Characters

Lentil is an important pulse crop with high nutritional value and high market price worldwide. Molecular markers have emerged as useful tools to assess the genetic diversity across crops. The study was conducted to explore genetic diversity of twenty lentil genotypes considering yield and yield attributing traits. Among all genotypes, BARI Masur-6, BARI Masur-7 followed by genotypes BD-3806 and BD-4090 showed the highest value of yield attributing traits therefore, these genotypes are considered as best performer. The results of cluster analysis based on the Ward’s method grouped the genotypes into three clusters and the genotypes of cluster III revealed the maximum value for yield per plants which indicated their importance in the selection for yield improvement program of lentil. Afterwards, 20 genotypes were evaluated through 7 sets of SSR primers to assess genetic diversity among the genotypes. Among them, four sets of primers viz., SSR 19, SSR 33, SSR 90 and SSR 213 showed high polymorphism which suggesting the greater genetic diversity in the genotypes. The unweighted pair group method of arithmetic mean (UPGMA) dendrogram based on Nei’s (1973) genetic distance led the genotypes into four major clusters which showed a bit deviation with the morphological cluster. The findings of this study will be very useful for selection of appropriate parents and the genetic understanding for the set up for future systematic lentil breeding programs.

English

Understanding the genetic variability and diversity of crops is the basis for breeding and improving of crops. Sixty four Ethiopian hot pepper genotypes were evaluated in 8×8 simple lattice design for genetic variability in green fruit yield and yield related traits at Axum Agricultural Research Center during 2018/2019 under irrigation. Data were collected on green pod yield and yield related characters. The analysis of variance showed significant amount of variations among genotypes in their mean performances of studied traits. High heritability and genetic advance were observed for average fruit weight (145.03, 97.11), fruit length (97.43,98.62), number of fruits per plant (78.54,95.78), number of branches per plant (77.65, 98.64), green pod yield per plant (74.26,99.80) and fruit pericarp thickness (63.61,97.76), respectively. This indicates that these traits are predominantly governed by additive gene action. From correlation study fruit yield per plant exhibited highly significant positive association with average fruit weight (0.72, 0.71), fruit length (0.69, 0.68) and fruit diameter (0.61, 0.60)) at both genotypic and phenotypic levels, respectively. Fruit length had the highest direct effect (0.46) on fruit yield per plant, followed by average fruit weight (0.36). In general, result of this study indicated that average fruit weight, fruit length, fruit diameter and fruit pericarp thickness showed high heritability, genetic advance, positive correlation and high positive direct effects. Hence, these traits can be used as indirect selection criteria for hot pepper yield improvement program. Key words: GCV, genetic advance, heritability, PCV, pod yield, variability. &nbsp

Genetic variability, heritability, correlation and path analyses of yield components in traditional rice (Oryza sativa L.) landraces

The presence of sufficient genetic variability, the knowledge of nature of association among different characters and relative contribution of different characters to yield is a prerequisite to any breeding programme. The aim of the present study was to estimate genetic parameters of thirteen yield and yield attributing traits in 40 landraces of rice with a view to select better yield attributes in rice. The higher value of phenotypic co-efficient of variation (PCV) compared to the corresponding genotypic coefficient of variation (GCV) for all the studied traits indicated that there was an influence of the environment. Number of unfilled grains per panicle exhibited high estimates of PCV and GCV followed by number of filled grains per panicle, number of grains per panicle, flag leaf area. High heritability coupled with high genetic advance was observed in flag leaf area, pollen fertility, number of grains per panicle and number of filled grains per panicle which reflected that the direct selection of these characters based on phenotypic expression by simple selection method for yield improvement would be more reliable Grain yield per plant showed significant and positive association with days to 50% flowering, days to maturity, flag leaf area, number of total tillers per hill, number of effective tillers per hill, pollen fertility, number of grains per panicle, number of filled grains per panicle indicating selection of these characters for yield improvement may be rewarding. Both at phenotypic and genotypic level, days to 50% flowering, flag leaf area, number of effective tillers per hill, pollen fertility, panicle length, number of grains per panicle and 100 seed weight had direct positive effect on yield per plant indicating their importance during selection in yield improvement program. Moreover, the information generated from this study, can be exploited in future rice breeding program. J. Bangladesh Agril. Univ. 17(1): 26–32, March 2019

Genetic association studies for yield and yield contributing traits in Plantago ovata Forsk.

Twenty four accessions of Plantago ovata were grown to study existing variability, correlation and cause and effect relationships between yield and its component traits with their possible view in future improvement programmes. Analysis of variances displayed highly significant differences among accessions for all the traits. High heritability (>75%) coupled with the high genetic advance (>30%) were observed for the traits viz., leaf width, number of spikes/plant, biological yield/plant and seed yield/plant suggesting predominance of additive gene action. Seed yield/plant exhibited highly significant and positive correlation with biological yield/plant followed by number of spikes/plant, effective tillers/plant, harvest index, seed weight/spike, spike weight and husk recovery both at genotypic and phenotypic level. Biological yield/plant, harvest index, spike weight, effective tillers/plant and husk recovery exhibited the highest positive and significant direct effect on seed yield/plant. Critical analysis of results obtained from character association and path analysis indicated that the traits viz., biological yield/plant, harvest index, spike weight, effective tillers/plant and husk recovery were of prime concern as they possessed high positive association and direct effects on seed yield/plant. These traits are more reliable for selection for yield improvement programmes in Plantago ovata.

Direct and indirect effects of cob traits on yield in exotic maize germplasm under nitrogen deficient conditions

Despite of adoption of hybrid maize cultivation to a considerable level, maize yields in Pakistan are lower than other countries in the region. With others, maize cultivation under low soil fertility and without supplemental nitrogenous inputs is an important reason for low yields. This derives national maize breeding programs to develop low-nitrogen responsive maize cultivars. In this context, exotic maize open-pollinated varieties were introduced from CIMMYT for adaptability testing and subsequent adaptation. The trial including these OPVs was planted under zero nitrogen application. Correlation and path coefficient analysis was used to establish association of grain yield with its components to ascertain specific selection criteria which will be used to enhance efficiency of the future maize breeding and yield improvement programs using this germplasm. The results complemented with heritability estimates revealed that 100-kernel weight and shelling percentage together with kernel rows per cob can be utilized effectively for yield enhancement under nitrogen deficient conditions. Keywords: Correlation; Low nitrogen; Maize; Path analysis; Yield http://dx.doi.org/10.19045/bspab.2017.600116

GENOMIC VARIATION OF FIVE INDONESIAN CACAO (Theobroma cacao L.) VARIETIES BASED ON ANALYSIS USING NEXT GENERATION SEQUENCING

<p class="abstrakInggris"><span>Indonesian cacao productivity is still low mainly due to the lack availability of superior cacao planting materials. A new breeding method is necessary to expedite cacao yield improvement programs. To date, no study has yet been done to characterize Indonesian cacao varieties at the whole genome level. The objective of this study was to characterize genomic variation of five superior Indonesian cacao varieties using next-generation sequencing. Genetic materials used were five Indonesian cacao varieties, i.e. ICCRI2, ICCRI3, ICCRI4, SUL2 and ICS13. Genome sequences were mapped to the cacao reference genome sequence of Criollo variety. Sequence alignment and genomic variation discovery were done using Bowtie2 and mpileup software of Samtools, respectively. A total of 2,326,088 single nucleotide polymorphisms (SNPs) and 362,081 insertions and deletions (Indels) were obtained from this study. In average, a DNA variant was identified in every 121 nucleotides of the genome sequence. Most of the DNA variants were located outside the genes. Only 347,907 SNPs and Indels (13.18%) were located within protein coding region (exon). Among the DNA variations within exon, 188,949 SNPs caused missense mutation and 1,535 SNPs induced nonsense mutation. Unique gene-based SNPs were also discovered from this study that can be used as fingerprints for the particular cacao variety. The DNA variants obtained were excellent DNA marker resources to support cacao breeding programs. The SNPs discovered are useful as materials for genome-wide SNP chip development to be used for gene and QTL tagging of important traits for expediting national cacao breeding program.</span></p>

English

The experiment was carried out to access the inter relationship of genotypes in their oil yield with seed yield, oil content and other yield components  and to determine cluster of white seeded sesame genotypes  and environments based on their oil yield. Seventeen sesame genotypes were tested at six environments in northern Ethiopia during 2015 main season. The experiment was laid out in Randomized Complete Block Designs (RCBD) with three replications across all the environments. Seed yield had a significant and positive correlation (P≤0.01) with number of branches (r = 0.414) and number of capsules (r =0.468). Positive correlation seed yield with number of capsules and number of capsules indicated that better yield can obtain from highly branched plants and high number of capsules because the number of capsules increases with the degree of branching. Seed yield was negative significant correlated with days to maturity (r =-0.500) and flowering time (r = -0.626), significant at (p≤0.05) and (p≤0.01), respectively. The negative association between seed yield and days to flowering and maturity indicated that moisture stress after flowering might have caused relatively a yield reduction in the late maturing genotypes. Whereas, the early flowering and early maturing genotypes can escape the moister stress conditions. Based on the cluster analysis of 17 white seeded sesame genotypes classified in to different four distinct clusters. Cluster II, III and IV had high mean yield, oil content and oil yield than the other clusters. Genotypes grouped in those clusters had also greater genetic divergence important for farther yield, oil yield and oil content improvement program breeding in northern Ethiopia. Sesame growing environments also clustered in to four groups. Environments grouped in Cluster I, II and IV had high seed yield, oil content and oil yield. Hence, environments grouped in those clusters are important for seed yield, oil content and oil yield production improvement program in the study areas.   Key words: Cluster analysis, correlation, dendrogram.

PEMANFAATAN TEKNOLOGI GENOMIKA DAN TRANSFORMASI GENETIK UNTUK MENINGKATKAN PRODUKTIVITAS KELAPA SAWIT / The Use of Genomic and Genetic Transformation Technologies for Oil Palm Productivity Improvement

One of the main constrains oil palm cultivation in Indonesia is the low productivity with national yield average of 4 ton oil/ha/year much lower than the yield potential of up to 18.5 ton oil/ha/year. Conventional breeding method is a slow process and time consuming. It takes 10-12 years just to complete a breeding cycle. Applying genomic together with DNA tansformation methods should expedite oil palm breeding program. The objective of this manuscript was to review the application of genomic and DNA transformation technologies to improve oil palm productivity and its potential use for yield improvement program in Indonesia. Genomic technology has resulted reference genome sequence map of two oil palm species (E. guineensis and E. oleifera) that resulted the isolation of Sh gene controlling oil yield heterosis, discovery of mantled fruit mechanism, and as a foundation for superior gene and tait-associated marker discoveries to accelerate oil palm breeding program. The use of Sh gene markers together with mantled fruit detection kit at early stages of plant development accelerates oil palm breeding cycle and facilitates mantled seedling detection to guarantee productivity improvement. Multiplication of superior individual plants using in vitro culture should guaranty plantation high productivity in the field. Genetic engineering technique is potentially applied to improve palm oil quality and nutrition content as well as developing products useful for producing bioplastics. Resequencing studies of three Indonesian oil palm genotypes resulted millions of genomic variations (SNPs and Indels) important for high valued breeding resources to accelerate national oil palm breeding programs. Genomic as well as DNA transformation technologies are potentially applied in Indonesia to support national oil palm productivity and oil quality improvement programs.

Evidence for the involvement of hydraulic root or shoot adjustments as mechanisms underlying water deficit tolerance in two Sorghum bicolor genotypes

Sorghum bicolor (L.) Moench is an ancient drought-tolerant crop with potential to sustain high yields even in those environments where water is limiting. Understanding the performance of this species in early phenological stages could be a useful tool for future yield improvement programs. The aim of this work was to study the response of Sorghum seedlings under water deficit conditions in two genotypes (RedLandB2 and IS9530) that are currently employed in Argentina. Morphological and physiological traits were studied to present an integrated analysis of the shoot and root responses. Although both genotypes initially developed a conserved and indistinguishable response in terms of drought tolerance parameters (growth rate, biomass reallocation, etc.), water regulation displayed different underlying strategies. To avoid water loss, both genotypes adjusted their plant hydraulic resistance at different levels: RedLandB2 regulated shoot resistance through stomata (isohydric strategy), while IS9530 controlled root resistance (anisohydric strategy). Moreover, only in IS9530 was root hydraulic conductance restricted in the presence of HgCl2, in agreement with water movement through cell-to-cell pathways and aquaporins activity. The different responses between genotypes suggest a distinct strategy at the seedling stage and add new information that should be considered when evaluating Sorghum phenotypic plasticity in changing environments.

Integrated Management of Faba Bean Black Root Rot (Fusarium solani) through Varietal Resistance, Drainage and Adjustment of Planting Time

Black root rot, caused by Fusarium solani, is one of the most important diseases of faba bean causing up to 70% on farm yield loss in severe conditions in Ethiopia. Integrated management is the most promising alternative to control the disease. Three faba bean varieties, two drainage methods and three planting dates were evaluated under high disease inoculum pressure on a sick plot for two consecutive cropping seasons in a 3×2×3 factorial experiment. Results showed that the resistant variety Wayu was least affected by the disease (18.86% dead plants at harvest) when sown early on a flat bed. The susceptible variety Kassa was highly affected by the disease (89%) on a raised bed. All the three varieties performed well on raised beds (41.16%) than on flat beds (51.29% dead plants). Early or late planting resulted in significantly lesser overall percentage of dead plants (38.85%) and (44.23%) respectively as compared to optimum planting date (55.59%). Significant interactions were observed between variety and drainage method (P=0.003, F = 6.94, df= 2) which resulted in the least percentage of dead plants (21% and 20% on a flat and raised bed respectively) of variety Wayu compared to the moderately resistant variety Wolki (69% on flat and 36% on raised) and the susceptible variety Kassa (63% flat and 67% raised). The yield (g/plot)also varied significantly with variety wolki giving the highest yield (856 g/plot ) followed by variety Wayu (883 g/plot ). It is concluded that all the three factors are important for management of the disease but emphasis should be given to varietal resistance and use of raised beds. The two varieties Wolki and Wayu are recommended with raised beds for higher yield and variety improvement programs.

Genetic Variability, Correlation and Path Coefficient Analysis of Morphological Traits in some Extinct Local Aman Rice (Oryza sativa L)

Thirty five local aman rice varieties were evaluated for their variability with regards to yield and yield components. Estimates of heritability and genetic advance in per cent of mean were also obtained for the above traits. In addition, studies on character associations and path coefficients were also undertaken. The highest σ2g was found for number of root hair (103415.40) and the lowest magnitude of σ2g was observed in number of primary branches per panicle (1.97). The highest σ2p was found for number of root hair (109410.31) and the lowest magnitude of σ2p was observed in number of primary branches per panicle (2.61). High GCV and PCV for number of effective tiller, root weight, number of root hair and grain yield per hill (g) indicated that selection of these traits would be effective. Correlation of Grain yield per hill was found to be highly significant and positive for number of root hair, days to flowering and plant height at both genotypic and phenotypic level and negatively significant for number of secondary branches per panicle at both level. Significant positive correlation of grain yield per hill with number of root hair, days to flowering and plant height implied that selection for these characters would lead to simultaneous improvement of grain yield in rice. Further, yield was observed to be positively associated with panicle bearing tillers and number of filled grains per panicle and these characters were noticed to exert high direct effects on grain yield per plant. High indirect effects of most of the traits were noticed mostly through panicle bearing tillers per hill indicating importance of the trait as selection criteria in crop yield improvement programs.

Yield improvement and yield variability reduction in an EOQ model with planned shortages and random yield

This paper reports the results of an investigation of a set of continuous time, constant demand inventory models under the condition of yield uncertainty. Specifically, the impact of yield improvement programs on lot size, backorder level, and the resulting costs are examined. Models for improving yield rate and reducing yield variability are developed and examined through a series of numerical exercises. In addition, a model for the simultaneous improvement of yield rate and yield variability is presented for the case where there is a relationship between the mean and variance of the yield distribution. In all cases, investment programs improve the picture with respect to manufacturing yield for processes which are not necessarily under statistical control.

Assesment of Cocoa Genotypes for Quantitative Pod Traits

Yield related traits in 20 cocoa genotypes were investigated to determine suitable parental genotypes for yield improvement programmes in cocoa. Fifteen uniformly ripe pods were collected for pod and bean characteristic assessment from twenty genotypes in an existing cocoa hybrid trial research plot laid out in a randomized complete block design with six replications at the Cocoa Research Institute of Nigeria (CRIN), Ibadan, Nigeria. Seven quantitative data on the pods were subjected to statistical analysis. The 20 genotypes differed significantly (P < 0.001) for the seven traits. Performances of the genotypes ranged as: pod weight (175.40 – 620.50 g), pod length (11.30 – 20.10 cm), pod width (6.37 – 8.90 cm), pod thickness (0.73 – 1.65 cm), number of beans per pod (20 52), weight of beans per pod (27.33–119.67 g) and dry weight of hundred beans Original Research Article Sobowale et al.; BBJ, 6(4): 146-153, 2015; Article no.BBJ.2015.037 147 (52.33 – 115 g). Positive and significant (P < 0.001) correlation existed between pod weight and length, pod width, pod thickness and weight of beans per pod. The range of broad sense heritability was between 56.13 (number of beans per pod) to 81.76 (dry weight of hundred beans). About 86% of the total variation was explained by the first three principal component axes and four distinct groups emerged from the clustering technique. Results show significant (P<0.05) intra-cluster variability of the seven traits and that choosing genotypes G3 (T65/7 x T9/15), G5 (P7 x T60/887), G6 (P7 x PA150), G15 (T86/2 x T22/28) and G16 (T82/27 x T12/11) as parents in future yield improvement programmes will enhance cocoa productivity in Nigeria.

Analysis of commercial proanthocyanidins. Part 4: Solid state 13C NMR as a tool for in situ analysis of proanthocyanidin tannins, in heartwood and bark of quebracho and acacia, and related species

(13)C NMR is an effective method of characterizing proanthocyanidin (PAC) tannins in quebracho (Schinopsis lorentzii) heartwood and black wattle (Acacia mearnsii) bark, before and after commercial extraction. The B-rings of the constituent flavan-3-ols, catechols (quebracho) or pyrogallols (wattle), are recognized in unprocessed source materials by "marker" signals at ca. 118 or 105ppm, respectively. NMR allows the minimum extraction efficiency to be calculated; ca. 30%, and ca. 80%, for quebracho heartwood and black wattle bark, respectively. NMR can also identify PAC tannin (predominantly robinetinidin), and compare tannin content, in bark from other acacia species; tannin content decreases in the order A. mearnsii, Acacia pycnantha (87% of A. mearnsii), Acacia dealbata and Acacia decurrens (each 74%) and Acacia karroo (30%). Heartwood from an underexploited PAC tannin source, Searsia lancea, taxonomically close to quebracho, shows abundant profisetinidin and catechin PACs. NMR offers the advantage of being applicable to source materials in their native state, and has potential applications in optimizing extraction processes, identification of tannin sources, and characterization of tannin content in cultivar yield improvement programmes.