COMBINING ABILITY STUDIES OF GRAIN YIELD AND RELATED TRAITS IN PEARL MILLET

The present study was undertaken to explore the genetic architecture of pearl millet through combining ability analysis in a 5X5 diallel fashion. Both GCA and SCA mean squares were significant in grain yield, plant height, panicle length and days to flowering. However, these were non-significant for number of productive tillers and panicle girth. General combining ability estimates revealed that genotype MGP-322 was good general combiner for all the traits under study except for days to flowering for which MGP-335 and 13RBS-01 were good general combiners but these were poor general combiners for all other traits under study. The crosses MGP-322XMGP-328, MGP-322XMGP-335, MGP-328X13RBS-13, 13RBS-01X13RBS-13 and MGP-322X13RBS-01 were best specific combiners for grain yield and some other attributes respectively. All these crosses involved at least one good general combiner except MGP-328X13RBS-13. This suggested that good general combiners are the best tool in improving the crop yield by manipulating the genetic architecture. Combining ability variances revealed that although both GCA and SCA variances were important, however, SCA variances were higher than GCA variances suggesting that non additive type of gene action was more prominent in the inheritance of characters under study

Developmental Change of Approximate Number System Acuity (Keenness) Reveals Delay

Purpose: Major aim of the study was to investigate the development of mathematical thinking and processing in Pakistani sample. Particular focus of the study was to figure out whether Pakistani people across various age groups process numbers with similar sophistication as their western counter parts from developed countries. Mathematics plays huge role in the development of the society and research evidence in this context from Pakistan is scarce. Design/Methodology/Approach: 261 participants ranging from 5 to 72 years of age participated in the study. Panamath task being the robust measure of ANS acuity was administered. Findings: Results revealed that numerical acuity got precise with an increase in age. However, most sophisticated acuity has been shown around age 46-50 as compared to the western population showing its peak around 30 years of age. Delay in developing most sophisticated approximate number system acuity across the groups as compared to the trend reported in the western population raises many questions in terms of cultural variations and practices contributing to the development of number sense. Implications/Originality/Value: We need to improve our mathematical learning and teaching practices so that it could be helpful in economic growth in turn by better mathematical performance across various age groups. On a general note, economical practices, math related curriculum policies, lack in math related games, math practices at home and at educational institutions with varying level of curriculum and pedagogical practices might be a contributor for this trend. The study has important implications for understanding the development of number sense cross-culturally keeping in view the evidence from various cultures.                                                           &nbsp

Effects of Non-Symbolic Approximate Number Practice on Symbolic Numerical Abilities in Pakistani Children

Current theories of numerical cognition posit that uniquely human symbolic number abilities connect to an early developing cognitive system for representing approximate numerical magnitudes, the approximate number system (ANS). In support of this proposal, recent laboratory-based training experiments with U.S. children show enhanced performance on symbolic addition after brief practice comparing or adding arrays of dots without counting: tasks that engage the ANS. Here we explore the nature and generality of this effect through two brief training experiments. In Experiment 1, elementary school children in Pakistan practiced either a non-symbolic numerical addition task or a line-length addition task with no numerical content, and then were tested on symbolic addition. After training, children in the numerical training group completed the symbolic addition test faster than children in the line length training group, suggesting a causal role of brief, non-symbolic numerical training on exact, symbolic addition. These findings replicate and extend the core findings of a recent U.S. laboratory-based study to non-Western children tested in a school setting, attesting to the robustness and generalizability of the observed training effects. Experiment 2 tested whether ANS training would also enhance the consistency of performance on a symbolic number line task. Over several analyses of the data there was some evidence that approximate number training enhanced symbolic number line placements relative to control conditions. Together, the findings suggest that engagement of the ANS through brief training procedures enhances children's immediate attention to number and engagement with symbolic number tasks

Number line placement test performance by children in the three training conditions of Experiment 2.

<p>(A) Accuracy in ordinality of children's placements. (B) Proportion of children with more linear placements (dark portion of bars) and with more logarithmic placements (lighter portion of bars). (C) Proportion of error in children’s placements, with smaller values corresponding to better performance.</p

Experiment 2 training task results.

<p>Average reaction time (A) and accuracy (B) for the first (easier) and second (harder) set of training trials.</p

Experiment 1 test results.

<p>Average speed (A) and accuracy (B) on exact, symbolic addition problems and approximate numerical comparison performance (C) by children in the two training conditions. Note: Performance accuracy in numerical comparison (C) is represented as a Weber fraction (<i>w</i>) derived from approximate, non-verbal numerical comparison performance, where smaller <i>w</i> values correspond to more precise ANS acuity.</p

Schematic depiction of magnitude training conditions in Experiments 1 & 2.

<p>Numbers depict important time points beginning from the presentation of the first array (1) to the end of the trial (5).</p

Cross-national study of quantity comparison abilities and math performance using Numeracy Screener

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