Hyperspectral spectroscopic reflectance data collected in-vivo non-symptomatic and symptomatic kiwi leaves in field conditions

Hyperspectral spectroscopic reflectance data collected in-vivo non-symptomatic and symptomatic kiwi leaves in field conditions Study Area The monitoring of kiwi plants (Actinidia deliciosa) was performed in two test sites, integrated in commercial orchards at Guimarães, Portugal, located in Caldas das Taipas (CT; 41°29′09.8′′ N 8°21′54.3′′ W) and Briteiros (BT; 41°30′53.3′′ N 8°19′20.5′′ W). In CT, the orchard was 5 years old (2020), and 12 female kiwi plants of the variety Bo.Erika®were assessed. In the BT test site, plants had 30 years old (2020), and 8 feminine plants of the same variety were selected to integrate the study. Visual disease identification (scouting) was accomplished by the detection of characteristic symptoms of bacterial kiwi canker, caused by Pseudomonas syringae pv. actinidiae on leaves (adaxial and abaxial sides). Samples were classified as asymptomatic (showing no symptoms) or symptomatic (presenting at least one typical chlorotic or necrotic spot). Spectral Ground Measurements Leaf hyperspectral data were obtained with a portable spectroradiometer (ASD FieldSpec® HandHeld 2, ASD Instruments, Boulder, CO, USA). Reflectance data were recorded in the wavelength range from 325 nm to 1075 nm, with 1 nm of spectral resolution. The spectroradiometer has a full conical field-of-view angle of 25°. During the data acquisition, the sensor was maintained 30 cm above the kiwi leaf, directed vertically downward (nadir view), giving a sampling footprint close to 13.3 cm. The leaf was placed upon a black card to reduce background noise. Prior to the hyperspectral acquisition, an internal dark calibration was performed, followed by a white calibration through a spectralon (white reference panel). Measurements were acquired in the nadir position, in cloud-free conditions, between 11:00 and 14:00 h (local time), minimizing changes in the solar zenith angle. Weekly hyperspectral data on plant’s reflectance were obtained between May and June 2020, which corresponded to the full development of Psa symptoms in kiwi plant leaves during the growing season. After, biweekly measurements were performed between July and August 2020. Three random leaves were chosen for each plant, and hyperspectral information was collected from one point, totaling 504 measurement points. In each spectral measurement, 10 repetitions were performed and later averaged to minimize the noise effect.本数据集包含田间条件下活体采集的无症状与染病猕猴桃叶片的高光谱反射光谱数据。 ## 研究区域 本研究针对猕猴桃植株（*Actinidia deliciosa*，美味猕猴桃）开展监测，共设置两个试验站点，均位于葡萄牙吉马良斯的商业果园内，分别为卡尔达斯达斯泰帕斯（CT；41°29′09.8″ N 8°21′54.3″ W）与布里特罗斯（BT；41°30′53.3″ N 8°19′20.5″ W）。CT站点的果园至2020年时已有5年树龄，共评估12株雌性‘Bo.Erika®’品种猕猴桃植株。BT站点的植株树龄为30年（2020年统计），选取同品种的8株雌性植株参与本研究。 ## 病害视觉鉴定（病害普查） 通过检测叶片（正面与背面）上由丁香假单胞菌猕猴桃致病变种（*Pseudomonas syringae pv. actinidiae*，简称Psa）引发的猕猴桃细菌性溃疡病典型症状，完成病害视觉鉴定。样本被划分为无症状组（未表现任何症状）与染病组（至少存在一处典型褪绿或坏死病斑）。 ## 地面高光谱测量 叶片高光谱数据采用便携式光谱辐射计（ASD FieldSpec® HandHeld 2，ASD仪器公司，美国科罗拉多州博尔德）采集。反射光谱数据的采集波长范围为325 nm至1075 nm，光谱分辨率为1 nm。该光谱辐射计的全锥形视场角为25°。数据采集过程中，传感器保持在猕猴桃叶片上方30 cm处，垂直向下（天底视角），采样光斑尺寸约为13.3 cm。将叶片置于黑色卡纸之上以降低背景噪声。高光谱采集前，先执行内部暗电流校准，随后通过光谱漫反射板（白色参考面板）完成白板校准。 所有测量均采用天底视角，在无云条件下于当地时间11:00至14:00之间开展，以最小化太阳天顶角变化带来的测量误差。2020年5月至6月期间，每周采集一次植株反射光谱数据，该时段对应猕猴桃叶片上Psa症状的全面显现期；2020年7月至8月期间，采集频率调整为每两周一次。每株植株选取3片随机叶片，每片叶片采集1个点位的高光谱信息，总计504个测量点位。每个光谱测量点重复采集10次，后续取平均值以降低噪声干扰。