Yield and water productivity of rice as affected by time of transplanting in Punjab, India

Early planting of rice crop during the period of peak evaporative demand results in substantial mining of ground water and threats the sustainability of rice production in Punjab, northwest India. In order to increase yield and water productivity, arrest the mining of ground water, and achieve sustainability of rice production, there is need to adopt water-saving management practices. The present investigation in the Indian Punjab was aimed at investigating the effect of date of transplanting in four rice cultivars varying in growth duration (short-duration RH-257 and PR-115, and medium-duration PR-113 and PAU-201) on yield and water productivity. Delaying in transplanting from 15 June to 25 June or 5 July resulted in reduction in mean grain yield of the four cultivars by 7.2% and 15.9%, respectively. PAU-201, a photoperiod-sensitive cultivar, had higher mean grain yield (7.8 t ha⁻¹) by 14.1%, 12.8% and 11.5% over the photoperiod-insensitive cultivars, PR-113, PR-115 and RH-257, respectively. Irrespective of transplanting dates, short-duration cultivars, RH-257 and PR-115, respectively, resulted in 18.9% and 16.6% saving of water, as compared to medium-duration cultivar PR-113. With delayed transplanting after 15 June, both yield and water productivity decreased for all photoperiod insensitive cultivars, but yields remained statistically similar and water productivity greater for a photoperiod sensitive cultivar. Mean irrigation water productivity (WP_I) was highest for 15 June transplanting (0.66 kg m⁻³) and lowest for 5 July transplanting (0.57 kg m⁻³), and was highest for RH-257 (0.68 kg m⁻³) and lowest for PR-113 (0.50 kg m⁻³). Total water productivity (WP_I+R; irrigation plus rainfall) decreased by 9.1% for 5 July transplanting compared with 15 June transplanting, and was highest for RH-257 (0.49 kg m⁻³) and lowest for PR-113 (0.38 kg m⁻³). Real crop water productivity (WP_ET) of the photoperiod insensitive cultivars decreased (1.10-1.40 kg m⁻³), but that of a photoperiod sensitive cultivar increased (1.63 kg m⁻³), with delayed transplanting. We conclude that substantial amount of water can be saved and yield increased by transplanting short-duration cultivars during the period of peak evaporative demand, or water saved and yield maintained by transplanting a photoperiod-sensitive cultivar late in the season when the evaporative demand is low.     

光周期不敏感切花菊种质创新研究进展

菊花是短日性植物,多数为秋菊,这给切花菊的周年生产带来很多困难.选育光周期不敏感、在自然条件下可周年生产的切花菊新品种,是国家863计划中切花菊育种的攻坚目标,也是切花菊生产大国日本的主攻目标之一.辽宁省农业科学院花卉研究所从1994年开始,应用花粉管通道法进行外源总DNA转导和杂交育种等方法,经过前后10余年的探索试验,选育出光周期不敏感的绿化菊(地被菊)和切花菊创新种质资源,为新品种选育奠定了基础.     

燕麦PRR基因家族鉴定与表达分析

春、夏播燕麦是长日照作物，光周期不敏感燕麦的创制使其在短日照条件下能正常生长发育。PRR基因是光周期途径中重要的昼夜节律调节基因。前期转录组研究表明PRR基因可能与燕麦光周期不敏感性有关。本研究从转录组和全基因组水平对燕麦PRR基因家族进行鉴定、生物信息学分析和表达研究。结果表明，在燕麦转录组和基因组水平分别鉴定到6个和2个PRR基因，均包含REC和CCT结构域；进化分析表明燕麦PRR基因与小麦、大麦、黑麦草和山羊草的亲缘关系较近；燕麦PRR基因启动子区域包含与光响应、生长发育和胁迫相关的顺式作用元件；qRT-PCR分析表明燕麦PRR基因的表达具有节律特征，全生育期过程中AsPRR1和AsPRR2在穗和叶的表达量均呈现由低到高、下降后再升高的双峰趋势，且AsPRR2基因的表达量高于AsPRR1。以上结果说明，AsPRR基因在燕麦光周期途径中发挥负调控作用，其下调表达促进了光周期不敏感性燕麦gp012在短日照条件下开花。本研究为揭示AsPRR基因在燕麦光周期不敏感机制中的作用奠定 了基础。