Application of vigor indexes to evaluate the cold tolerance in rice seeds germination conditioned in plant extract

Abstract

Rice is a crop that presents sensitivity to cold, especially in the germination phase, which leads to high economic losses. Alternative management forms are essential to increase tolerance to low temperatures, and seed priming represents a promising tool. The objective of this study was to investigate the priming effect of the aqueous extract of carrot roots on rice seeds to increase tolerance to low temperatures during germination. Seeds from cultivars BRS Querência (cold-susceptible) and Brilhante (cold-tolerant) were soaked for 24 h in concentrations of 0, 25, 50, and 100% carrot extract, sown on germitest paper and conditioned in BOD for 21 days at 15 °C. As a control, the seeds soaked in water were also germinated at 25 °C. They were evaluated for germination, first germination count, and germination speed index to calculate the stress indices: tolerance index, susceptibility index, and harmonic mean. They were also evaluated for the length and dry mass of shoot and root. The results showed that the rice seeds conditioning in carrot extract effectively reduces the damage caused by cold, significantly increasing the germination speed and the percentage of final germination and the growth evaluations, more expressive at 100% concentration. The stress indexes are efficient in estimating the tolerance of the cultivars and the effect of the different conditions in low-temperature conditions, highlighting the superiority of the Brilhante cultivar.

Evaluation of the effect of phenolic pigments on rice germination under low temperature conditions

“…At 27 days after sowing (second count), 96% germination was observed in the cultivar Bojuru and below 75% in the other cultivars. Low temperatures significantly reduce the germination ability of rice, and this result was also verified by PEYMAN & HASHEM (2010), SHARIFI (2010), DA MAIA et al (2017), DIEN & YAMAKAWA (2019), TEIXEIRA et al (2021), VIANA et al (2021. The percentage and germination speed can be influenced by several factors such as water, light and temperature.…”

“…The percentage and germination speed can be influenced by several factors such as water, light and temperature. Temperature acts directly on seed imbibition and on biochemical reactions that regulate the metabolism involved in the germination process (TEIXEIRA et al 2021). 1 PCG_C: first germination count, at 3 days, in the control (%); Ger_C: final germination count at 14 days, in the control (%); PCG_ LT: first germination count, at 20 days, in cold condition (%); Ger_ LT: final germination count, at 27 days, in cold condition (%).…”

“…In addition of crop development stage, the injury caused by low temperatures is influenced by the intensity and duration of this stress (TEIXEIRA et al 2021). In Rio Grande do Sul (RS), the main riceproducing State in Brazil, low temperatures are common in the germination stage, since sowing is performed soon after winter.…”

“…In Rio Grande do Sul (RS), the main riceproducing State in Brazil, low temperatures are common in the germination stage, since sowing is performed soon after winter. This condition can be extended to mid-spring, resulting in delayed germination and seedling emergence for more than 20 days (TEIXEIRA et al 2021). Low night temperatures may also occur during the reproductive stage.…”

Genome-Wide Dissection of Novel QTLs and Genes Associated with Weed Competitiveness Traits Using a Population of Early-Backcross Selective Introgression Lines of Rice (Oryza sativa L.)

“…These associations align with previous ndings highlighting the importance of these ESG traits in determining rice competitiveness against weeds. However, inconsistencies arise regarding root length correlations with ESG traits, contrasting with previous reports (Teixeira et al 2021). A fundamental principle of crop-weed competition underscores the advantage of early establishment, emphasizing the critical role of emergence time in eld competitiveness (Swanton et al 2015).…”