Nondestructive Phenomic Tools for the Prediction of Heat and Drought Tolerance at Anthesis in Brassica Species

Table 2

The mean squares (MS) and degrees of freedom (df) of treatments and residuals for genotype (G), heat (H), drought (D), and their interactions for 11 phenomic traits and 3 agronomic traits as measured on 12 Brassica genotypes from 1 to 7 days after treatments (DAT) during anthesis. The statistical significance of main effects and interactions is shown as 0.01 < p < 0.05 () and p < 0.01 (). “ns” and “NA” indicate “not significant” and “not applicable,” respectively.


Trait	DAT	Source of variation														Residuals
		G		H		D		G×H		G×D		H×D		G×H×D		Residuals
		df =11		df =1		df =1		df =11		df =11		df =1		df =11		df	MS

(i) Six in-cabinet rapid phenotyping traits

PRI	1	0.0040		0.0006			ns		ns		ns		ns		ns	96	0.0001
	3	0.0028		0.0007			ns		ns		ns		ns		ns	96	0.0001
	5	0.1000			ns		ns	0.1093			ns		ns		ns	96	0.0049
	7		ns		ns	0.0005			ns		ns		ns		ns	96	0.0001

Qy	1	0.0260		0.0060			ns		ns		ns		ns		ns	96	0.0010
	3	0.0419			ns		ns		ns		ns		ns		ns	96	0.0007
	5	0.0318			ns	0.0069			ns		ns		ns		ns	96	0.0008
	7	0.0409		0.0156		0.0330			ns		ns	0.0336			ns	96	0.0014

T1	1		ns	71.700			ns		ns		ns		ns		ns	96	5.6368
	3	118.452		89.508			ns		ns		ns		ns		ns	96	3.3334
	5	122.400		67.800		97.300			ns		ns	86.500			ns	96	5.3684
	7	123.480			ns	193.590			ns		ns	61.460			ns	96	4.7786

T2	1	132.360		462.590			ns		ns		ns		ns		ns	96	5.9198
	3	179.160		264.880		96.86			ns		ns	42.140			ns	96	5.1332
	5	284.740			ns	599.43			ns		ns	255.470			ns	96	8.1280
	7	203.710		31.920		1187.95			ns		ns	219.530			ns	96	6.3080

T3	1	207.403		169.743			ns		ns		ns		ns		ns	96	6.7461
	3		ns	33.046		55.406			ns		ns	29.348			ns	96	4.6506
	5	101.137			ns	209.639			ns		ns	51.073		100.395		96	4.9548
	7		ns		ns	418.200			ns		ns	55.600			ns	96	5.2742

LC	1	447132			ns		ns		ns		ns		ns		ns	96	7670.82
	3	440562			ns	211692			ns		ns	91991			ns	96	4992.83
	5	263299		28906		539613			ns		ns	63756			ns	96	5936.44
	7		ns	18381		651370			ns		ns		ns		ns	96	3676.20

(ii) Three photosynthetic traits derived from A/Ci curve

Vcmax	1	38159		201158		2100		35625		17665			ns		NA	12	293.98
	3		ns	191108			ns		ns		ns		ns		NA	12	2407.81
	7		ns	17042		39130			ns		ns	17887			NA	12	1018.22

ETR	1	16189		2031			ns	4424			ns		ns		NA	12	114.25
	3	8118		2337			ns		ns		ns		ns		NA	12	285.85
	7		ns	10776		23629			ns		ns	7068			NA	12	886.04

TPU	1	117.500			ns		ns		ns		ns		ns		NA	12	1.9685
	3	53.700		16.300			ns		ns		ns		ns		NA	12	1.5817
	7	153.900			ns	96.100			ns	125.300			ns		NA	12	3.6774

(iii) Two plant growth imaging-derived phenotyping traits

VolWP	3	463877			ns	19157			ns	31012			ns		ns	96	1245.17
VolWP	7	261725		30020		267973			ns	126866			ns		ns	96	1461.15

VolF	3	102.935			ns		ns	20.590			ns	3.112			ns	96	0.5380
VolF	7	241.570		18.740		65.870		34.950		54.320		5.680			ns	96	1.1831

(iv) Three agronomic traits

FW	7	101256		116824		1238679		6001		41512		10410		5545		48	1883.69

SY	At harvest	12.789		14.719		4.490			ns		ns		ns		NA	12	0.9399

SW	At harvest	0.0198		0.0101			ns		ns		ns		ns		NA	12	0.0015

G×H: Genotype by Heat interaction; G×D: Genotype by Drought interaction; H×D: Heat by Drought interaction; G×H×D: Genotype by Heat by Drought interaction.
The phenomic traits include (i) six in-cabinet rapid phenotyping traits: photochemical reflectance index (PRI), photosystem II quantum yield (Qy), leaf conductance (LC), and the temperature differences between (a) bud and ambient environment (T1), (b) leaf and ambient environment (T2), and (c) bud and leaf (T3); (ii) three photosynthetic traits derived from A/Ci curves: maximum carboxylation rate allowed by Rubisco (Vcmax), photosynthetic electron transport rate (ETR) and the rate of triose phosphate use (TPU); and (iii) two plant growth imaging derived phenotyping traits: whole plant volume (VolWP) and flower volume (VolF).
The agronomic traits include fresh weight (FW) of the whole plant at DAT7, and seed yield (SY) and 100-seed weight (SW) of each plant at maturity.