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20142
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Subject: Agricultural Meteorology × End date: 2014 × Start date: 2014 ×
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    Growth dynamics of mustard (Brassica napus) cultivars under modified microclimatic environments
    (Punjab Agricultural University, Ludhiana, 2014) Brar, Sunwinderpal Singh; Sidhu, Prabhjyoti Kaur
    The field experiment entitled “Growth dynamics of mustard (Brassica napus) cultivars under modified microclimatic environments” was carried out at the Research Farm, School of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana during the Rabi 2012-13. Field experimentation on Brassica napus cultivars (GSC-6 and Hyolla PAC 401), comprising of two spacings (30 cm and 45 cm) and three dates of sowing i.e., D1 (26 October, 2012), D2 (10 November, 2012) and D3 (27 November, 2012) was planned in split plot design and replicated thrice. Three dates of sowing and two cultivars were assigned as main plot treatments and two spacing levels as sub plot treatments. The results revealed that the solar radiation (SR) interception and photosynthetically active radiation (PAR) interception was higher under the first date of sowing and in cv. Hyolla PAC 401. Similarly the SR and PAR interception was higher under closer row spacing (30 cm) due to taller plant height. Canopy temperature and relative humidity was slightly higher under first and third date of sowing. With delay in sowing, the reduction in days taken by phenological events of crop leads to shortening of vegetative and reproductive growth stage of crop and cv. GSC-6 took 7, 5 and 9 days less number of days to attain physiological maturity as compared to cv. Hyolla PAC 401 under first, second and third date of sowing, respectively. Periodic plant height and dry matter accumulation was found higher under first date of sowing as well in closer row spacing (30 cm). Leaf area index (LAI) was higher under first date of sowing and crop sown with closer row-spacing (30 cm) and in cv. Hyolla PAC 401. Amongst the yield attributes characters, first date of sowing crop produced higher number of branches, number of seeds/pod and 1000-seed weight. Both the cv. showed non-significant effect on number of branches, seeds/pod and 1000-seed weight. Whereas closer row spacing (30 cm) produced higher number of branches/plant, number of seeds/pod and 1000-seed weight as compared to wider row spacing (45 cm). The pod yield, seed yield, biological yield and straw yield were significantly higher under the first sown crop and in closer row spacing (30 cm). The agro climatic indices GDD, PTU, HTU and HUE attained were more under first date of sowing and were accrued more by cv. Hyolla PAC 401 as compared to cv. GSC-6 under all three date of sowing. The growth parameters like CGR, RGR, LAD, SLW and NAR showed increasing trend, i.e., increased with advancement in sowing from November to October. On the other hand, LAR and SLA showed reverse trend, i.e., increased with delay in sowing from October to November.
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    Microclimate modification in gobhi sarson (Brassica napus L.) by debranching and defoliation under different dates of sowing
    (Punjab Agricultural University, Ludhiana, 2014) Harinder Pal Singh; Dhaliwal, L.K.
    The experiment was conducted at the Research Farm, School of Climate Change and Agricultural Meteorology, Punjab Agricultural University, Ludhiana to study “Microclimate modification in gobhi sarson (Brassica napus L.) bydebranching and defoliation under different dates of sowing” during rabi season of 2013-14. The experiment was laid out in split plot design with three sowing dates (October 10, October 25 and November 10) and two varieties (GSC-6 and GSL-2) in main plots; and debranching and defoliation treatments along with the control in sub plots with three replications. The number of days taken for different phenological events of crop reduced with delay in sowing from 10th October to 10th November which shortened the vegetative and reproductive phase. The photosynthetically active radiation interception was higher in variety GSC-6 at pod formation and pod filling stages while at flowering stage, it was higher in variety GSL-2. In defoliation and debranching treatments PAR interception was increased by 4 to 7 per cent over control. The agrometeorological indices viz. growing degree days (GDD), photo-thermal units (PTU), helio-thermal units (HTU) were higher under 10th October sowing and decreased with each delay in sowing. The relative humidity was low under debranching and defoliation treatments. There was a slight increase in canopy temperature was also found under defoliation and debranching treatments over control. Crop sown in October recorded higher number of primary branches per plant, number of secondary branches per plant siliquae per plant, seeds per siliquae and test weight as compared to November sown crop. Varieties showed non-significant differences in all the above parameters except test-weight. Defoliation treatment recorded significantly higher number of secondary branches and siliquae per plant than debranching and control, however, significantly higher number of seeds per siliqua and test weight was recorded in debranching treatment over defoliation and control. Variety GSC-6 produced higher seed yield than GSL-2, with significant decrease in 10th November sown crop as compared to October sowing. Debranching produced significantly higher yield followed by defoliation and control in 10th and 25th October sown crop. However, November sown crop resulted in significantly lower seed yield in defoliation treatment, while debranching and control produced similar seed yield. The information from this study will help in management of microclimate through canopy modification and agronomic means, which could result in higher productivity of gobhi sarson. Moreover, the defoliation and debranching of gobhi sarson provides the fodder yield in addition to seed yield, which may compensate the labour cost involved in such practices.