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A field experiment conducted for screened 288 elite gen pool of linseed against bud fly infestation at Kanpur, India during rabi 2011-12 and 2012-13. The flowering duration showed significant positive relationship (r=0.9278 and 0.9368) with bud infestation. The maximum flowering duration 32.80 and 31.44 days was recorded on variety A-44 with highest bud infestation of 62.29 and 69.99 percent during respective years against variety C-C-1-2 which had a shortest flowering duration of 8.80 and 12.94 days with the minimum 16.38 and 14.30 percent bud fly infestation. The sepal thickness negative highly significant relationship (r=--0.7224) with bud infestation. The resistant germplasm line maximum sepal thickness (0.49 mm) had relative minimum bud infestation (6.88%) while minimum sepal thickness (0.24 mm) with maximum bud infestation(65.11%), plant height, flower colour did not show significance in bud fly resistance, whereas, flowering duration bud as well as sepal thickness showed significant impact.

A field experiment conducted for screened 288 germplasm of linseed against bud fly infestation at Kanpur, Uttar Pradesh during rabi season to study the historical basis of resistance of linseed against bud fly. The results indicated that the sepal thickness negative highly significant relationship (r=--0.7224) with bud infestation. The resistant germplasm line maximum sepal thickness (0.49 mm) had relative minimum bud infestation (6.88%) and was statically at par other resistant germplasm lines viz. A-95B, CI-1385, EC-1392, EC-1424, GS-234, IC-15888 and JRF-5. While minimum sepal thickness (0.24 mm) with maximum bud infestation (65.11%) which was statically at par with other susceptible lines viz. Ajgan-3-1, Ajgan-20M, Alipur (Hamirpur), Anand, GS-148, GS-440, Gunawal Local, NP (RR) 193, RAULD-7810, RLC-28 (PM), MS-14, SJKO-2, SJKO-45. The genotypes with minimum thickness of sepal suffered maximum bud infestation as compared to those with maximum sepal thickness.

A field experiment conducted for screened 288 elite gen pool of linseed against bud fly infestation at Kanpur, India during rabi 2011-12 and 2012-13. The flowering duration showed significant positive relationship (r=0.9278 and 0.9368) with bud infestation. The maximum flowering duration 32.80 and 31.44 days was recorded on variety A-44 with highest bud infestation of 62.29 and 69.99 percent during respective years against variety C-C-1-2 which had a shortest flowering duration of 8.80 and 12.94 days with the minimum 16.38 and 14.30 percent bud fly infestation. Categorization on the basis of flowering duration and damage caused by the bud fly, were found, flowering duration range (11.80- 18.30) and (12.94-21.44), number of entries 11 and 8 were resistant, (0-10 %), flowering duration range (11.80-20.80) and (11.44-25.94), number of entries, 164 and 146 moderately resistant, (10 to 25%), flowering duration range (12.80-30.80) and (11.44- 28.94), number of entries 98 and 116 moderately susceptible, (25 to 50%), flowering duration range (24.80-33.30) and (21.94-32.44), number of entries 15 and 18 susceptible, (50 to 75%), none of the varieties found highly susceptible (more than 75%) to be bud fly attack during 2011-12 and 2012-13, respectively. The variety having longer flowering duration was severely infested by bud fly as compared to those with shorter flowering duration.

A field experiment conducted for screened 288 elite gen pool of linseed against bud fly infestation at Kanpur, India during rabi 2012-13 to study the bud structure of resistance of linseed against bud fly. The results indicated that the bud length and width showed significant positive correlation coefficient relationship (r=0.1559 and 0.0761) bud infestation. The resistant germplasm line minimum (GS-234) minimum bud length and width (7.93 ×3.26 mm) had relative minimum bud infestation (6.88%) and was statically at par other resistant germplasm lines viz. A-95B, CI-1385, EC-1392, EC-1424, GS-234, IC-15888 and JRF-5. While susceptible germplasm line (Arny) exhibited maximum bud length and width (8.25 ×3. 23 mm) maximum bud infestation(65.11%) which was statically at par with other susceptible lines viz. Ajgan-3-1, Ajgan-20M, Alipur (Hamirpur), Anand, GS-148, GS-440, Gunawal Local, NP(RR)193, RAULD-7810, RLC-28(PM), MS-14, SJKO-2, SJKO-45.

In this paper we examine the hypothesis that diapause induction in the polyvoltine pod midge Dasyneura brassicae Winn. (Diptera: Cecidomyiidae) is controlled by cumulative global solar radiation during the larval stage. The correlation between field observations of relative diapause for 3 years and four environmental factors (daylength, temperature, cumulative daylight time, and cumulative global solar radiation) was investigated. The cumulative global solar radiation during the larval stage clearly showed the strongest correlation with the observed relative diapause. It was estimated that larvae which cumulated less than 71.1 kWh m-2 entered diapause. Compared to former theories on diapause induction in insects, this hypothesis explains how temperature and light can function together and, furthermore, it removes the requirement for biological clock involvement in diapause induction in insects.