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Sugarcane plays a crucial role in global sugar and ethanol production. Conventionally, sugarcane propagation involves planting billets. However, Brazilian researchers have introduced the innovative pre-sprouted seedlings (PSS) method, widely used in the MEIOSI (Simultaneously Occurring Interrotational Method) system. Although PSS has several advantages over the conventional method, its sensitivity to water scarcity is a challenge. This study aimed to evaluate the survival and growth of PSS inoculated with Bacillus licheniformis and Bacillus subtilis (PGPB) under different water regimes. The experiment was conducted in the field in a randomized block in strips (split-block) using a 2 × 4 factorial scheme consisting of two inoculation conditions (with and without PGPB) and four water regimes (WR) (0%, 33%, 66%, and 100% of the ideal irrigation). PGPB increased PSS survival (4.17%) and water use efficiency (185.10% under the 0% WR). In addition, inoculation increased root (12.5%, 7.7%, and 16.2% for surface area, area projection, and root volume, respectively) and shoot growth. PGPB also increased nutrient uptake, such as N (60.8% and 18.3% under 0% and 66% WR), P (on average 11.7%), Mn (27.6% and 28.7% under 66% and 100% WR), Zn (111.4% under 0% WR), and Cu accumulation (27.17%), which provided a higher number of stalks per meter and, therefore, a higher multiplication rate in the MEIOSI system. Inoculation proved to be a promising alternative for PSS establishing under water restriction. [ABSTRACT FROM AUTHOR]

Water deficiency is one of the most limiting abiotic factors to sugarcane world production (Saccharum spp.). Data on chlorophyll content and gas exchange are used to select genotypes tolerant to water deficit. However, these variables are influenced by environmental factors, which vary intensely throughout the day. Thus, this research aimed to evaluate the influence of diurnal variation of gas exchange, leaf water potential, chlorophyll content, and SPAD index on the differentiation between genotypes tolerant and susceptible to water deficiency. The greenhouse experiment was conducted in a completely randomized 2 × 2 × 4 factorial scheme, with two varieties (RB867515/RB855453), two soil water tensions [without water deficiency (–D) and with water deficiency (+D)], and four evaluation times (7 am, 10 am, 1 pm, and 4 pm) with four replicates. RB867515 maintained greater CO2 assimilation, stomatal conductance, transpiration rate, intrinsic transpiration efficiency, leaf water potential, total chlorophyll content, and SPAD index under +D, regulating carbon gain about water loss and providing greater shoot biomass under +D compared to RB855453. The best times to perform the measurements for selecting tolerant genotypes based on physiological traits and specifically on the SPAD index are at 10 am and between 7 am and 10 am, respectively. [ABSTRACT FROM AUTHOR]

Using chemical ripeners in the sugarcane favors the increase of sucrose productivity, regulates the effects of adverse weather conditions for ripening, and promotes the anticipation of harvest. However, it can also modify the nutrient absorption, translocation, and accumulation process and, consequently, affect the nutrient cycling of the straw maintained on the soil surface. Thus, this research aimed to evaluate ripeners' effects (glyphosate − 0.5 L ha−1; sulfometuron-methyl − 0.02 kg ha−1, and trinexapac-ethyl − 0.8 L ha−1) on the nutritional status of the sugarcane leaf canopy. Natural ripening maintained the highest levels of P and Zn throughout the time. The highest levels of N, P, and K were provided by trinexapac-ethyl in most of the evaluated periods, as well as contributing to the highest levels of Ca, Mg, and S, along with sulfometuron methyl, from 30 to 60 days after application (DAA). The highest levels of B and Zn were observed under sulfometuron methyl. On the other hand, glyphosate was the ripener responsible for the lowest nutrient concentrations in the leaf canopy, including N, Ca, Mg, and S at 45 DAA and B and Mn at 30 and 45 DAA. Considering the importance of maintaining the straw for nutrient cycling, in addition to being a ripener, trinexapac-ethyl contributed to the maintenance of high levels of nutrients in the leaf canopy in relation to the other ripeners, which suggests a greater possibility of availability of these nutrients for the ratoon development in the upcoming cycles. [ABSTRACT FROM AUTHOR]

Silicon (Si) has been associated with minimizing water deficit damage in several plants, but its effects on physiological aspects and gas exchange responses for sugarcane during the ripening phase are still scarce. Therefore, this study aimed to determine whether Si fertilization enhances physiological and gas exchange responses, biomass and sugar production in response to water deficit during the ripening phase of sugarcane, and whether these responses are similar in drought-tolerant and drought-sensitive cultivars. A greenhouse experiment was conducted using two sugarcane cultivars (RB855536 is drought-sensitive; RB867515 is drought-tolerant) without and with Si (0 = zero and 1000 kg−1 Si; -Si and + Si) under well-watered or water deficit conditions at the ripening phase. The biometric, physiological, and gas exchange measurements were independently influenced by the water deficit, cultivar, and Si. The leaf Si concentration, chlorophyll a (Chla), carotenoids, net CO2 assimilation rate (A), electron transport rate (ETR), plant transpiration (E), stomatal conductance (gs), and sugar content in stalks increased with Si, and electrolyte leakage (EL), plant length, leaf area (LA), and stalk fresh biomass decreased. Water deficit decreased the leaf water potential (ψW), fresh biomass of leaves, and LA. RB867515 showed higher LA, plant length, and fresh leaves biomass, while RB855536 showed superior leaf Si, Chla, Chlb, carotenoids, A, ETR, E, sugar content, and EL and lower ψW. Si fertilization promotes enhancement in some physiological and gas exchange aspects and increased sugar contents in stalks, independent of the water deficit at ripening phase or the drought tolerance of sugarcane cultivars. [ABSTRACT FROM AUTHOR]

Since climate changes have caused water restrictions, safflower stands out as an alternative crop due to its adaptability to restrictive soil and climate conditions. Thus, this research aimed to evaluate the physiological and yield performance of four safflower lines (IMA 02, IMA 04, IMA 14, and IMA 21) under two water regimes [without water deficiency—around 22% soil moisture content—100% of field capacity (FC); and with water deficiency—50% of FC]. The water regimes were imposed for 30 days during the flowering phase, followed by rehydration for 20 days. Water deficiency decreased relative water content, water potential, photosynthetic pigment contents, photosynthetic performance, maximum variable and potential quantum yield of PSII, electron transport rate, and photochemical quenching. In contrast, it increased electrolyte leakage, water use efficiency, and non-photochemical quenching. The decreases in photochemical efficiency and photosynthetic performance as a function of water deficiency caused reductions in the number of capitula, 100-grain mass, and harvest index, with more significant reductions in IMA 02, which was considered susceptible to soil water changes. IMA 04, IMA 14, and IMA 21 were considered tolerant because their physiological variables and yield components were less affected by water restriction, and they also showed recovery after rehydration compared to IMA 02. Thus, these lines can be recommended for commercial use, and safflower breeding programs aiming to select superior genotypes under drought conditions. [ABSTRACT FROM AUTHOR]

Appropriately using phosphorus (P) for the fertilization of sugarcane is critical to achieving high productivity because it is one of the most limiting nutrients in agricultural cropping systems. Thus, the objective of this research was to evaluate the morphological, biochemical, and yield responses of sugarcane, and the soil microbial–chemical properties, under the use of organomineral fertilizer (OF) associated or not with Bacillus velezensis strain UFV 3918 (B) combined with mono ammonium phosphate (MAP) doses. The experimental design used was completely randomized, consisting of eight treatments [Control (3/3 MAP); OF (without MAP); OF + 1/3 MAP; OF + 2/3 MAP; OF + 3/3 MAP; B + OF + 1/3 MAP; B + OF + 2/3 MAP; B + OF + 3/3 MAP] and four replicates. B + OF + 1/3 MAP provided increases in accumulated soil basal respiration (11.9%), carbon of microbial biomass (35.9%), fluorescein diacetate (12.7%), arylsulfatase (25.5%), and acid phosphatase (10.1%) activity compared to the control, which implied in higher shoot and total biomass. These results present a potential strategy for sugarcane fertilization, using bacteria in combination with OF to improve P nutrition and growth in sugarcane with reduced economic and environmental impact. [ABSTRACT FROM AUTHOR]

Sugarcane is one of the main crops in Brazilian agriculture. It has high economic and productive potential, but its current productivity is still lacking due to poor nutritional management in both the soil and the plant. Zinc (Zn) directly affects tillering and plant growth, which are critical factors to sugarcane productivity and ratoon longevity. Thus, this research aimed to evaluate the effects of Zn chelate doses (185, 260, and 330 g ha−1) and two application methods (furrow and foliar applications) on the tillering, yield, and quality of sugarcane. The Zn chelate fertilization via furrow at a dose of 330 kg ha−1 provided increases of 13.59%, 17.6%, and 17.0% in stalk height (SH), stalk (TSH) productivity, and sugar (TPH) productivity, respectively. In contrast, Zn foliar application at a dose of 260 g ha−1 provided increases of 3.71%, 20.7%, and 17.0% in SH, TSH, and TPH, respectively. The optimal Zn chelate fertilization in sugarcane cultivation can be performed at a dose of 330 g ha−1 via furrow application at planting or at a dose of 260 g ha−1 via foliar application 145 days after planting. [ABSTRACT FROM AUTHOR]