http://www.erepo.iihr.ernet.in/handle/123456789/52 Fri, 17 May 2013 01:53:59 GMT 2013-05-17T01:53:59Z http://www.erepo.iihr.ernet.in/handle/123456789/258 Title: Role of information technology in developing statistical models for horticultural crops research Authors: R, Venugopalan; M R, Hegde; S, Thippeswamy Abstract: Application of statistical techniques in agricultural science has gained momentum in the last two decades due to the advances in information technology. Complex statistical algorithms were used at ease through advanced programming tools. An attempt has been made in this communication to bring out the salient results achieved in statistical research with information technology as a backbone. Results pertaining to studies on crop modeling, canopy architecture models, biometrical research and disease forecasting for perennials were discussed. Computer programs/software were developed to facilitate these studies using C-compilers, SQL, .NET platform. Thu, 01 Jan 2009 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/258 2009-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/236 Title: A statistical model for describing the epidemiology of incidence of downy mildew in grapes Authors: Rawal, R D; Venugopalan, R; Saxena, A K Abstract: Statistical models were developed to optimize the role of ecological variables and simultaneously to predict downy mildew incidence in grapes (cv Anab-e-Shahi) at Indian Institute of Horticultural Research, Bangalore, India. Further, as a measure of goodness-of-fit, the coefficient of determination (R2) was used to evaluate the empirical models developed. The initial results indicated only 39% of the variability in per cent disease incidence was reflected collectively by preceding week’s ecological variables viz., minimum temperature (X1), maximum temperature (X2), relative humidity at 07.30 h (X3) and at 13.30 h (X4), evaporation (X5), amount of rainfall (X7) and wind speed (X6). This may be due to reason that per cent disease incidence was in the range zero to as high as 90% during the period of study. To eliminate such a high variability, new models were developed separately for severity less than 10% and severity exceeding 40%. Correlation analysis showed that that both maximum and minimum temperatures negatively whereas humidity levels both at morning and evening h were positively influenced towards the absence of disease incidence. The results indicated that if the disease severity was less than 10%, about 65% of the variability in per cent disease incidence followed the equation of y = –12.29 – 0.065 X1 – 0.04 X2 +0.01 X3 + 0.156 X4 – 0.53 X5 – 0.31 X6 + 0.03 X7. Correlation analysis in case of high disease incidence showed that relative humidity, maximum temperatures, wind speed and number of rainy days jointly influenced the disease. In the case of high severity about 60.3% variability in per cent disease incidence followed the equation of y = 88.23 – 4.17 X1 +3.43 X2 –1.77 X3 + 0.83 X4 +3.06 X5 +1.36 X6 –0.41 X7. This model would be highly useful in predicting the disease severity and thereby programming for the disease management could be worked out, which will further reduce the fungicide load on the vine. Tue, 01 Jan 2008 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/236 2008-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/140 Title: Augmented BIB Design-an alternative statistical design in germplasm evaluation trials Authors: R, Venugopalan; K R M, Swamy; M K, Chandra Prakash Abstract: Randomized Block Design (RBD) is commonly employed to evaluate a set of germplasm accessions (test treatments) along with local checks. In such a trial, if test treatments under evaluation are high in number and availability of seeds is limited, an alternate experimental design needs to be employed. As a remedy, Balanced Incomplete Block Design (BIBD), which estimates treatment contrast with more precision and treatments are not repeated in all the blocks, unlike in RBD, may be used. Such a constructed layout, not only saves precious seed material from test treatments, but also directly reduces the cost of all related inputs such as labour, water, fertilizer, pesticide etc. These factors were elucidated in the evaluation of 100 accessions of okra along with four check varieties (Arka Anamika, Arka Abhay, Parbhani Kranti and PB-7) using Augmented BIB Design with six blocks, in the Division of Vegetable crops at I.I.H.R., Bangalore during Kharif 2005. Results showed that by adopting BIB experimental design, instead of the regular complete block design, 60.2 % of the land area required for conducting germplasm evaluation in okra could be reduced. Tue, 01 Jan 2008 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/140 2008-01-01T00:00:00Z http://www.erepo.iihr.ernet.in/handle/123456789/139 Title: Association of fruit traits and aril browning in pomegranate (Punica granatum L.) Authors: S H, Jalikop; R, Venugopalan; R, Kumar Abstract: Abstract Pomegranate cultivation is one of the most attractive farming enterprises in the Indian arid tropics. However, the quality of the fruit is often severely affected by a physiological disorder called ‘aril browning’ in which a part or all the arils show discolouration (browning) and such fruits are unfit for consumption. This has become a serious concern to consumers, growers and researchers in the recent times. In order to understand the genotypic variation for aril browning and its association with other fruit traits, 158 progenies obtained by selfing two pomegranate multiple hybrids viz., {(‘Ganesh’ 9 ‘Kabul’) 9 ‘Yercaud’} 9 {(‘Ganesh’ 9 ‘Gulsha Rose Pink’)- F2} and {(‘Yercaud’ 9 ‘Jyothi’) 9 (‘Ganesh’ 9 ‘Gulsha Rose Pink’)-F2} 9 {(‘Ganesh’ 9 ‘Kabul’) 9 ‘Yercaud’} were studied. Because of heterozygous nature of the crop and diverse genetic base of parents, a wide array of recombinants were produced which were scored for aril browning, fruit skin colour, aril colour, total soluble solids (TSS) and seed mellowness. Results of Spearman’s correlation analysis revealed that aril browning is inversely related with aril colour (r = -0.41). A statistical model constructed to study the reasons for the observed variation in aril browning showed that about 82.9% of it was accounted collectively by skin colour, aril colour, TSS and seed mellowness. Further, a refined model represented by Y (aril browning severity) = 0.78 - 0.52 X1 (aril colour) ? 0.23 X2 (TSS) was found to contribute to 73.5% of the observed variability in aril browning with least error in prediction. Analysis of data further showed that every unit increase in intensity of aril colour amounted to decrease in severity of aril browning by 0.52 units. However, for every unit increase in TSS there was an increase of 0.23 units in severity of aril browning. Thus, with the increase in intensity of aril colour there was a reduction in severity of aril browning while with raise in TSS, aril browning incidence was higher, an association often not favourable in selection of desirable genotypes. The results of the present study suggested that while developing varieties free from aril browning it is important to strike a balance between aril colour and TSS level. Fri, 01 Jan 2010 00:00:00 GMT http://www.erepo.iihr.ernet.in/handle/123456789/139 2010-01-01T00:00:00Z