Influence of low tunnel on production of bottle gourd (Lagenaria siceraria Mol.) grown under low temperature stress in semiarid conditions of Rajasthan

Abstract Cucurbits are basically tropical or sub-tropical which require warm growing season and in north Indian plains temperature goes down up to 0 o C during winter season, which prevent early season cultivation of cucurbits. Protected structures are advantageous for advancing the crop by 45-60 days than their normal season, quality produce, high yield and high return. Low tunnel is aflexible transparent polythene covering, which is installed over the rows or individual beds of transplanted or direct sown vegetables. Polythene low tunnel is one of the low cost production tool of vegetables. The field experiments were carried out at Agricultural Research Station, Durgapura, Jaipur during three consecutive years from 2009-10 to 2011-12 to identify suitable sowing date coupled with early and high yield having high net return of bottle gourd under polythene low tunnels. The experiment was laid out in randomized block design comprising ten different dates of sowing/transplanting in open field as well as under low tunnel at 15 days interval from 15 th November to 28 th February. The tunnel was made 7.5 x 0.7 m with the galvanized iron arches (hoops) of 6.0 mm size were fixed at 1.5 m apart to support the polythene over tunnels. After sowing, tunnels were covered with transparent non-perforated 40 micron ultra violet (UV) polythene sheet up to 15 th February. Perusal of three years pooled data showed that the sowing under different conditions had significant effect on days to first harvest, number of fruits per plant and fruit yield of bottle gourd. Days taken to first fruit harvest were reduced with the advancement in sowing dates. The maximum number of marketable fruits per plant (6.8) and marketable fruit yield (389.72 q/ha) of bottle gourd var. Warad was found when crop was shown on 30 th December under polythene low tunnel which was statistically at par with 15 th December sown crop under low tunnel condition, where as minimum number of fruits per plant (1.6) as well as fruit yield (128.43 q/ha) was recorded under 28 th February sowing in open field condition. The maximum net return (Rs. 297813.00) per hectare with B: C ratio of 3.24 was also recorded with 30 th December sown crop under low tunnel followed by 15 th December sowing under the low tunnel conditions. Result from this investigation showed that sowing on 15 th to 30 th December was proved best date with respect to highest number of fruits per plant and early fruit yield and the same dates were found profitable with a B:C ratio of 3.24.