Quantifying Effects of Photoperiod, Temperature and Humidity on Flowering Initiation in Basmati Rice Lines

Tahir Latif,Sadia Gull,Rana Ahsen Raza Khan,Awais Riaz,Muhammad Ramzan,Abid Mahmood,Zulqarnain Haider,Muhammad Akhter

doi:10.4236/ajps.2019.106064

Abstract

The results suggested that all the pure Basmati lines or genotypes initiate flowering within a specific range of day length duration and temperature. Delaying the transplanting date did not significantly affect the flowering time of studied Basmati lines. Maximum threshold of daily minimum temperature (MT) was 24°C during both the years. Likewise, maximum threshold of daily day-length (DL) durations was 12 hours and 18 minutes during both the study years. Results showed that the flowering was maximum when the MT and DL values were optimum as depicted by peak of the trend lines, where maximum lines flowered. Maximum flowering initiations took place when DL was about 11 hours and 15 minutes indicating Basmati as short day plant which flowers maximum when day lengths are shorter and dark or night duration is longer. During 2013, 1st date trial showed strong relationship between flowering initiation with dates of flowering during the flowering period as depicted by higher regression (R2 = 0.837) values. In 2nd date trial during the same year, the value is lower (R2 = 0.513) depicting less relationship of flowering initiation with the dates of flowering. The same trend was observed in 2014 trial. In 1st date trial, strong relationship between flowering initiation with dates of flowering during the flowering period as depicted by higher regression (R2 = 0.864) values, was observed. In 2nd date trial during the same year, the value is lower (R2 = 0.1789) depicting very poor relationship of flowering initiation with the dates of flowering, and the same trend (R2 = 0.0544) in 3rd date of trial.

Highlights

Basmati is the type of rice (Oryza sativa L.) which is long, slender-grained aromatic rice traditionally from Pakistan and India
The results suggested that all the pure Basmati lines or genotypes initiate flowering within a specific range of day length duration and temperature
Results showed that the flowering was maximum when the minimum temperature (MT) and DL values were optimum as depicted by peak of the trend lines, where maximum lines flowered

Summary

Introduction

Basmati is the type of rice (Oryza sativa L.) which is long, slender-grained aromatic rice traditionally from Pakistan and India. Basmati rice is considered sensitive to photoperiod as well as temperature, and is highly affected by these climatic factors resulting in significant yield fluctuations. Time of transplanting is the most important factor among all the agronomic components of yield that directly affect the yield in any crop especially in Basmati rice (Oryza sativa L.) varieties or lines [1]. Three climatic factors i.e. Photoperiod sensitivity, Temperature and Humidity are reported to caste crucial effects in flowering of the Basmati rice lines. Pure Basmati lines only flower between specific ranges of these climatic factors. Any fluctuation in these factors during flowering time results in incomplete flowering. Most of the Basmati rice cultivars are naturally bred to flower between the temperature ranges from 20 to 25 Celsius [2]. Pure Basmati lines twitches anthesis in the last week of September when temperature falls below 25 degree Celsius and completes in flowering within first week October until the temperature falls below 20 degree Celsius

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Results

Conclusion